PC Comscope Bit Error Rate Testing
PC Comscope Emulate Program
PC Comscope HDLC Protocol Decode Program
PC Comscope X.25 Protocol Decode Program

1.0 INSTALLING THE COMSCOPE UNIT

The Comscope unit simply plugs into one of the serial ports on your PC. Plug the 9 pin 'D' connector into the 9 pin 'D' connector on your PC. The Comscope can be powered either from a single 9 Volt alkaline battery or with the 120 Volt A/C wall adapter. The battery is installed by sliding open the battery compartment on the top side of the Comscope unit. The battery may be left in while using the AC wall adapter. The battery will not run down as long as the AC adapter is plugged into the Comscope unit, or the On/Off switch on the front of the unit is off. Push the On/Off switch to the depressed position before running the software.

The Comscope software will automatically find which serial port the Comscope is connected to (as long as the unit is turned on.) However, the Comscope software will load slightly faster if you save a new default configuration (see 5.5 below.) Simply go to the HARDWARE menu and hit ENTER to save the address the Comscope software has identified.

1.1 Installing the Software

Make a copy of the distribution diskette. If you will be running the Comscope from hard disk we recommend you create a separate directory and copy all files from the disk to this directory.

There are three programs on the distribution diskette.

CGA. exe, EGA.exe, and MONO.exe. The CGA program will run on CGA, EGA, or VGA displays and uses the 320x200 graphics mode for data display. The EGA program will run on EGA or VGA displays and uses the soft font mode for data display. The EGA display shows more data and is somewhat faster. The MONOchrome program is intended for monochrome displays but will also work on color.

1. To make a working copy of the diskette:

• insert diskette in drive a:
  
• insert a blank diskette in drive b: if you have one, or follow DOS prompts to insert blank disk in a:
  
• enter DISKCOPY A: B: at the DOS prompt

2. To install programs on a hard disk:

• make hard disk current disk
  

  e.g. enter C: at the DOS prompt

• create the directory for the Comscope programs:
  

  enter MD 904 at the DOS prompt
  enter CD 904 at the DOS prompt
  

• Insert the working copy of the diskette in drive a:
  

  enter COPY A:*.* at the DOS prompt

3. Copy the program for the adaptor you are using (CGA, EGA, or Monochrome) to a file named OM.EXE

• enter:
  

  COPY CGA.EXE OM.EXE at the DOS prompt or
  COPY EGA.EXE OM.EXE or
  COPY MONO.EXE OM.EXE

4. Type OM at the DOS prompt to start the program.

• You may also automatically start an application by entering the name (without the .OM4 extension) after OM:
  

  enter OM APP _NAME at the DOS prompt

  
  The Comscope will search for APP_NAME.OM4 in the current directory and start it if found.

There are five types of files that the Comscope will look for or create in the current working directory:

CONFIG.OM3: This file contains the hardware address of the Comscope board, the default monitoring mode, the default print setting, and the screen color.

xxxxxx.OM1: files with an .OM1 extension are files of captured data (or 'journal' files.)
You may examine the data by selecting a file from the EXAMINE FILE menu (section 5.4)

xxxxxx.OM2: files with an .OM2 extension are configuration files. You may have several predefined operating modes which may be selected from the CANNED CONFIGURATION menu (section 5.2.)

xxxxxx.OM5: files with an .OM5 extension are display code translation files. The names appear in the CODE menus of the mode sub-menus (e.g. Section 7.6).

xxxxxx.OM4: files with an .OM4 extension are executable application programs. These programs are selected via the PROGRAM OPTION menu (Section 5.3).

xxxxxx.OM6: These are the program files for the co-processor in the Comscope unit.

2.0 THE ELECTRICAL INTERFACE

The Comscope directly supports the RS-232 electrical interface. Other interfaces are supported through optical adapters. The Comscope can passively monitor an RS-232 line or it can emulate a DTE or DCE device. If the Monitor/Emulate switch is in the IN position the Comscope will passively monitor the circuit. If the Monitor/Emulate switch is OUT, the Comscope will drive certain signals on the circuit, based on THE DCE/DTE switch. If the DCE/DTE switch is IN, the Comscope will emulate a DTE. If the DCE/DTE switch is OUT, the Comscope will emulate a DCE.

The following table lists the signals supported by the Comscope. An 'x' shows those pins that are driven by the Comscope when emulating a DTE or DCE.

The Comscope is shipped with a 'T' cable for tapping into the circuit you are testing. One leg of the 'T' cable plugs into the 25 pin 'D' connector on the rear of the Comscope unit. The data line cable must be disconnected and both ends plugged into the 'T' cable. For instance, you would remove the cable from a modem and then plug the cable and the modem into two connectors on the 'T' cable. The Comscope can then capture and display the activity on the data line.

3.0 USING THE COMSCOPE

3.1 Navigating the menus
The Comscope program has been designed to be as self explanatory as possible without obstructing the experienced user. You select the various operating modes from menus. Each menu screen has a list of key words across the top. You 'pull down' the menu associated with the key words by using the left and right arrow keys at the right of your keyboard. Make sure the 'Num Lock' key is not on. The up and down keys select the particular option within each pull down menu. The selected option is high lighted with a green bar and the cursor will be flashing at the right of the selection. Some menu options allow you to enter a value, such as a baud rate. Options of this type are prefaced by a ">." Use the up or down arrow key to move the green bar to the "" then enter the appropriate value from the keyboard. Each menu screen will also list several function keys, which are the "F1" through "F10" keys along the left side or top of your keyboard. Depressing the appropriate key will immediately execute the indicated action, such as quitting the program (F-10.)

The bottom line of each menu screen is the explanation line, which gives a brief description of what each menu means. The line directly above this, which is usually blank, is the error line. If an error occurs, such as entering a file name that is not valid an error message will be displayed on this line, which will be accompanied by a beep from the speaker. Certain errors, such as leaving the door on your floppy disk open, will cause a small box to appear in the center of your screen with a brief explanation of the problem. The ENTER, or RETURN key is used as an 'execute' command. This key is used in several menus throughout the program. The explanation line at the bottom of the screen will indicate the action of the ENTER key for those menus.

3.2 Viewing data line activity
You will likely use the Comscope most often to view activity on a data line. In 'live mode' the Comscope captures data line activity and displays it on the screen as it is happening.

'Capture' means that the Comscope is actually keeping an internal history of that activity, so that you can stop monitoring and look back through the data, in 'review mode.' You may also store this history in a file called a journal file. The data can then be examined at another time and even another PC. This also allows you to save more data line history than the Comscope can hold in memory. The Comscope can store 64 KBYTES of data, without journalling, before the data is overwritten by new data.

In order to view data line activity you must tell the Comscope what type of data is on the data line. You do this by selecting the mode from the main menu and the parameters within that mode from the individual mode sub menus. Once you have selected a data mode you can save it to a named configuration file for later use or as the configuration the Comscope will default to when first started. The selected mode also identifies the type of data an application program will generate, unless the application program overrides the selected mode. The Comscope does a minimal amount of interpretation of data it assembles individual bits into characters and identifies certain low level error conditions. In the synchronous protocols the Comscope delineates data blocks as well. Higher level analysis of line data is accomplished with application programs.

3.3 Setting search sequences
The Comscope provides a powerful aid in looking for specific data line occurrences. You can use the Search Menu to identify certain sequences of events. You can direct the Comscope to highlight data or to freeze the display when the sequence occurs. The Search Menu is also useful in searching through captured data.

3.4 Running an application program
The Comscope includes an Application Program Interface (API) that allows application programs to vastly extend the capabilities of the Comscope. These programs can analyze and generate line data, allowing protocol decode, emulation's, error rate analysis, and more. These application routines must include their own documentation to explain their use. Two programs are included with the Comscope and their use is explained in Section (14.)

The following sections describe the various menus and what they mean. You may find it helpful to step through the program on your computer as you read the following sections.

4.0 MAIN MENU FUNCTION KEYS

4.1 F3 - Review Captured Date
If no application program has been selected, depressing function key F3 will put the Comscope in review mode (section 13), allowing you to review captured data line activity. Captured data remains in memory until overwritten by new data.

Shift F3 Depressing the Shift key and F3 simultaneously will deselect any application routine and enter review mode. Application programs must be deselected before reviewing captured data.

4.2 Shift F4 - Print Captured Data
Depressing the Shift key and function key F4 simultaneously will bring up the Print menu, which allows you to print a copy of data in the capture buffer. See Section 14.

4.3 F5 - Save Current Configuration
You may generate a named copy of the currently selected configuration for future use as described in Section 5.2 below. Depressing function key F5 will cause a box to appear in the center of the screen. Enter the name you want the configuration saved under. If you enter the name of a configuration that already exists the previous configuration will be overwritten. Do not use any extension (no'.') in the name. The Comscope will save the configuration in a file with the name you selected and the extension "OM2."

4.4 F6 - Define A Search Sequence
The Comscope allows you to set up a sequence of events that it will search for. The sequence may be searched for in live data line activity or in captured data. The search facility may also be used by an application program. Depressing function key F6 will bring up the search menu where the sequence can be set up. See Section 11.

4.5 F7 - Toggle Control Lead Capture
When control lead capture is ON the Comscope will capture all control lead changes as well as displaying them. If control lead capture is OFF the Comscope will display the state of the leads but not capture them, so that control lead changes will not show in a journal file or when Reviewing Captured Data. The control leads are displayed at the lower left of the screen. Inverse video (black letters in a white box) indicates that the control lead is 'on.' while normal video indicates that the lead is 'off.' (see Section 2.0.) NOTE: There are situations where noise on unused control leads can consume excessive processor time and buffer space and control lead capture must be OFF. Depressing F7 will switch control lead capture ON and OFF as shown to the right of the F7 prompt at the lower middle of the screen.

4.6 F8 - Toggle Time Stamping
When time stamping is enabled the Comscope will place time stamps in the capture buffer. The time (to 1/100s seconds) will be displayed in the lower right corner of the data screen when in captured mode. Time stamping is given a lower priority than displaying data so that at higher data rates the time stamps may be rather infrequent.

Time stamping can quadruple the size of the real time buffer so you may wish to turn it off when journalling data.

Depressing F8 will switch time stamping ON and OFF as displayed to the right of the F8 prompt at the lower right of the screen.

4.7 F9 - View Data Line Activity
If no application program has been selected (Section 5.3) depressing function key F9 will cause the Comscope to immediately enter live mode to display data line activity. See Section 12.

If an application program has been selected it will be started, with the application directly accessing the serial data line.

Shift - F9 Depressing the Shift key and F9 simultaneously will de-select any application routines and cause the Comscope to enter live mode.

4.8 F10 - Exit Program
Depressing F10 will exit the Comscope program and return control to DOS. This key has this function at all times in the program.

5.0 MAIN MENU

This screen is entered when the program is first started. You will be in the MODE menu (5.1 below) when the program starts. This screen has six pull down menus: PROGRAM OPTION, CANNED CONFIGURATION, MODE, EXAMINE FILE, HARDWARE ADDRESS, and seven function keys, described in Section 4.

5.1 MODE
This mode identifies the type of data that is to be monitored or generated: ASYNCHRONOUS, SYNCHRONOUS, HDLC, or UNKNOWN. These modes are described further under the individual sub-menu for the selected mode.

5.2 CANNED CONFIGURATION
The Comscope allows you to have a number of pre-defined named operating modes. These configurations are stored in files names xxxxxx.OM2, where xxxxxx is the file name displayed in this menu. These configurations are generated by depressing function key F5 (Sections 4.2 and 6.4.) The Comscope only displays the configurations found in the current directory. You may also select the ">" option and enter the DOS path name of a configuration file not shown. Do not enter the "OM2" extension.

Depressing function key F9 will load the highlighted configuration and immediately start monitoring or running the selected application program. If you wish to view or change the configuration before monitoring depress ENTER. Depressing the ENTER key will load the configuration and take you to the appropriate sub-menu.

5.3 PROGRAM OPTION
This menu lists the application programs found in the current directory. Application programs are named xxxxxx.OM4, where xxxxxx is the name displayed in this menu. You may also select the ''' option and enter the DOS path name of an application program not shown. Do not enter the .OM4 extension. You can also enter the full name (with extension of an application program. CAUTION: This option will allow you to run any file whether it is a legitimate executable program or not, which may hang your system or worse.

Once an application routine has been selected it will replace the normal live or captured mode functions. The application program is started:

1. By hitting function key F9 (section 4.6.) In this case the application routine is dealing with live data from and/or to the serial data line. The application can only generate line data if a DTE or DCE emulating adapter is installed (Section 2.)
2. By hitting function key F9 (section 4.6.) In this case the application will be receiving data that has previously been captured.
3. By selecting a file from the EXAMINE FILE menu (section 5.4.) In this case the application will be receiving data from the selected file.

The source of the data is almost completely transparent to the application. A protocol decode program, for instance, can decode live data or data previously journalled to a file.

5.4 EXAMINE FILE
This menu lists files of journalled data found in the current directory. Journalled data are stored in files named xxxxxx.OM1, where xxxxxx is the name displayed in this menu. You may also select the ">" option and enter the DOS path name of a file not shown. Do not enter the ".OM1" extension. These files are created by selected the JOURNAL option from the mode sub-menus (Sections 7.7, 8.9, 9.6, and 10.7.)

If an application program has been selected (section 5.3) it will process data from the selected file. Not all applications will give meaningful results in this mode. If no application program has been selected you will be able to view the data in captured mode (Section 13.)

Depressing the ENTER key will cause the Comscope to display a pseudo menu which displays the options which were in effect when the data was recorded. You will be prompted to hit any key, after which the Comscope will enter captured mode or start the selected application program.

5.5 HARDWARE ACCESS
This menu identifies the hexadecimal base address of COM port the Comscope unit is connected to (Section 15.) The Comscope software will display the addresses of all COM ports identified by your PC's BIOS. You may select one of these or enter a different value at the ''' option.

The hardware address is stored in a file called CONFIG.OM3. This file also contains the default configuration that the Comscope will use when first started. To establish a new default configuration you must first select the desired options and then go to this menu. Hit the ENTER key to save the new configuration.

6.0 SUB-MENU FUNCTION KEYS

The mode sub-menus are entered by depressing ENTER when in the MODE menu of the main menu (section 5.1.) All four sub-menus have the same nine function keys defined.

6.1 F2 - Main Menu
Depressing function key F2 will return you to the main menu (Section 5.)

6.2 F3 - Review Captured Data
If no application routine has been selected, depressing function key F3 will put the Comscope in review mode (Section 13), allowing you to review captured data line activity. Captured data remains in memory until overwritten by new data.

Shift - F3 Depressing the Shift key and F3 simultaneously will de-select any application routine and enter review mode. Application programs must be deselected before reviewing captured data.

6.3 Shift F4 - Print Captured Data
Depressing the Shift key and function key F4 simultaneously will bring up the Print menu, which allows you to print a copy of data in the capture buffer. See Section 14.

6.4 F5 - Save Current Configuration
You may generate a named copy of the currently selected configuration for future use as described in Section 5.2 above. Depressing function key F5 will cause a box to appear in the center of the screen. Enter the name you want the configuration saved under. If you enter the name of a configuration that already exists the previous configuration will be overwritten. Do not use any extension (no '.') in the name. The Comscope will save the configuration in a file with the name you selected and the extension ".OM2."

6.5 F6 - Define A Search Sequence
The Comscope allows you to set up a sequence of events that it will search for. The sequence may be searched for in live data line activity or in captured data. The search facility may also be used by an application program. Depressing function key F6 will bring up the search menu where the sequence can be set up. See section 11.

6.6 F7 - Toggle Control Lead Capture
When control lead capture is ON the Comscope will capture all control lead changes as well as displaying them. If control lead capture is OFF the Comscope will display the state of the leads but not capture them, so that control lead changes will not show in a journal file or when Reviewing Captured Data. The control leads are displayed at the lower left of the screen. Inverse video (black letters in a white box) indicates that the control lead is 'on,' while normal video indicates that the lead is 'off' (see section 2.0). NOTE: There are situations where noise on unused control leads can consume excessive processor time and buffer space and control lead capture must be OFF. Depressing F7 will switch control lead capture ON and OFF as shown to the right of the F7 prompt at the lower middle of the screen.

6.7 F8 - Toggle Time Stamping
When time stamping is enabled the Comscope will place time stamps in the capture buffer as often as possible. The time (to 1/100s seconds) will be displayed in the lower right corner of the data screen when in captured mode. Time stamping is given a lower priority than displaying data so that at higher data rates the time stamps may be rather infrequent or even nonexistent. Time stamping can as much as quadruple the size of the real time buffer so you may wish to turn it off when journalling data. Depressing F8 will switch time stamping ON and OFF as displayed to the right of the F8 prompt at the lower right of the screen.

6.8 F9 - View Data Line Activity
If no application program has been selected (section 5.3) depressing function key F9 will cause the Comscope to immediately enter live mode to display data line activity. See Section 12.

If an application program has been selected it will be started, with the application directly accessing the serial data line.

Shift - F9 Depressing the Shift key and F9 simultaneously de-select any application routines and cause the Comscope to enter live mode.

6.9 F10 - Exit Program
Depressing F10 will exit the Comscope program and return control to DOS.

7.0 ASYNCHRONOUS SUB MENU

This screen is entered by depressing ENTER when ASYNCHRONOUS is selected in the MODE menu in the main menu (section 5.1.) This screen has six pull down menus - SPEED, BITS/CHAR, STOP BITS, PARITY, CODE, and JOURNAL, and eight function keys.

7.1 General Information
The Comscope samples data with a clock 16 times the bit rate. It expects one start bit and at least one stop bit time. Application programs can generated data with 1, 1.5, or 2 stop bits. Absence of a stop bit is called a framing error. The Comscope expects and generates data with the low order bit transmitted first. Characters with parity or framing errors are displayed in color.

7.2 SPEED
This menu selects the bit rate of the data. You may select one of the listed rates or enter the decimal value of a different rate at the ""option. The maximum rate is 115200. Allowable rates are defined by the formula bit rate = 230400/x where x is an integer (whole number) between 2 and 65535. If you enter a non-allowable rate it will be mapped to the next higher allowable rate.

7.3 BITS/CHAR
This menu selects the number of data bits in each character, not including parity, start, or stop bits. If less than 7 bits/characters is selected the unused bits will be displayed as '0's.

7.4 STOP BITS
This menu selects the number of stop bits for data generated by an application program. Asynchronous data can be generated with 1, 1.5, or 2 stop bits. (The Comscope can receive any data with 1 or more stop bits.)

7.5 PARITY
If selected, the Comscope will check each data character for either even or odd parity. Characters with bad parity are displayed in color. Application programs can generate data with the parity selected by this menu. The parity bit is the high order bit i.e. the last bit transmitted before the stop bit.

7.6 CODE
The Comscope will display the names of all the code translation files (files with .OM5 extension) in the current directory. Select the name corresponding to the coding of the data you are monitoring. Note that you can switch between hexadecimal and the selected code while monitoring or scrolling through data (Sections 12.5 and 13.15.) Data generated by an application program will be translated to the selected code as listed in the tables in the PROGRAMMERS MANUAL.

7.7 JOURNAL
The Comscope allows you to save a copy of captured line data to a disk file for later analysis (see 5.4 above.) Journal files are named xxxxx.OM1, where xxxxx is the name displayed in this menu. This menu displays the names of journal files already existing in the current directory. You may select one of them or enter a new name at the ">" option. Do not enter the ".OM1" extension. Note that if you select a file that already exists the previous data will be overwritten.

8.0 SYNCHRONOUS SUB MENU

This screen is entered by depressing ENTER when SYNCHRONOUS is selected in the MODE menu (section 5.1). This screen has eight pull down menus, CODE, PAD CHAR, BITS/CHAR, SYNC SEQUENCE, DATA, ORDER, SPEED, and JOURNAL, and eight function keys. The eight function keys functions are described in section 6 above.

8.1 General Information
The Comscope supports character oriented synchronous protocols such as BiSync. These types of protocols assign special meaning to various characters or character sequences and use these special characters to delimit data and manage the data link. The Comscope does not support character count protocols such as DECs DDCMP. the Comscope can be set to search for any 6, 8, 12, or 16 bit synchronization sequence. It will display data received after this sequence until two consecutive PAD characters are not displayed. The Comscope does not check parity or CRC in this mode. The Comscope can support data with the least significant or most significant bit of each character transmitted first. It supports data with normal or inverted polarity.

The Comscope also has two special modes for IBM BiSync and IPARS data. The Comscope will verify the CRC of data frames in these modes. The special modes are selected via the BCC menu, as described below.

Data blocks generated by application programs in synchronous mode will begin with the selected synchronization sequence and end with a two character CRC-16 sequence and at least one pad character. Idle time between frames consists of pad characters. Application programs may also generate synchronous frames without the CRC characters. Note than an application program may override one or more of the options selected.

8.2 CODE
The Comscope will display the names of all the code translation files (files with .OM5 extension) in the current directory. Select the name corresponding to the coding of the data you are monitoring. Note that you can switch between hexadecimal and the selected code while monitoring or scrolling through data Sections 12.5 and13.15). Data generated by an application program will be translated to the selected code as listed in the tables in the APPLICATION manual.

8.3 Parity
The Comscope will check for even or odd parity if selected. Characters with the wrong parity will be displayed in color. The parity bit is in addition to the bits/character selected in 8.6 below: for instance 7 data bits with even parity is interpreted by the Comscope as 8 bits/character total.

8.4 BCC - Block Check Character.
When CRC-16 is selected, the Comscope will interpret line data as IBM BiSync. The Comscope automatically recognizes both transparent and normal data. In this mode, the last character of a frame with CRC will be highlighted if the CRC is correct. If the CRC is not correct the last character of the frame will be displayed in color. When CRC-6 is selected and Bits/Character is set to 6, the data will be interpreted as IPARS. The last character of frames with CRC will be displayed the same way as BiSync.

8.5 Pad Char
The Comscope interprets two successive pad characters as the end of a block. This menu displays the hexadecimal value of the pad character. you can enter the hexadecimal value of the pad character at the "" prompt. Note that only the number of bits selected in 8.7 below will be significant. Idle time between data blocks generated by an application program will be continuous pad characters.

8.6 BITS/CHAR
This menu selects the number of data bits in each character. If less than 8 bits per character are selected the unused upper bit(s) will be displayed 0s. Note that the number of bits per character selected also affects the synchronization sequence used, as described in 8.5 above.

8.7 SYNC SEQUENCE
This menu selects the sequence used to establish character synchronization. You may select either a one or two character sequence. If the number of bits per character is 5 or 6 the synchronization sequence will be one or two bit characters, i.e. 6 or 12 bits long for 7 or 8 bits per character the synchronization sequence will be 8 or 16 bits long. Enter the hexadecimal value of either one or two characters (separated by a comma) at the "" prompt. If the Comscope does not see a comma in the third position it will search for a single character synchronization sequence.

Data blocks generated by an application routine will be preceded by the synchronization sequence selected in this menu.

8.8 DATA
This menu selects whether the data has normal or inverted polarity. See the page for the electrical interface adapter you are using to identify what normal polarity is. This menu also selects the polarity of the data generated by an application routine.

8.9 ORDER
This menu selects whether data is transmitted with the least significant or most significant bit first.

8.10 SPEED
This menu selects the bit rate of the clock that will be generated by the Comscope when emulating a DCE.

8.11 JOURNAL
The Comscope allows you to save a copy of captured data to a disk file for later analysis. See Section 7.7 above.

9.0 HDLC SUB MENU

This screen is entered by depressing ENTER when HDLC is selected in the MODE menu (section 5.1). This screen has six pull down menus, IDLE, DATA CODING, BITS/CHAR, CODE, SPEED, and JOURNAL, and eight function keys. The functions of the eight function keys are described in Section 6 above.

9.1 General Information
High level Data Link Control (HDLC) is the frame level definition that is the basis for a number of modern protocols such as SDLC and X.25. There are only two special characters: flag and abort. A flag character is '01111110' and abort is any sequence of 7 or more consecutive '1's. Flag characters are used to delimit a frame of data. The two bytes immediately preceding the closing flag are the CRC error checking bytes. An abort terminates the frame being transmitted and indicates that it is not valid. Zeros are inserted in the data stream after five consecutive '1's so that will never appear as a flag or abort character. The Comscope will display the last character in a frame (normally the second CRC byte) in the opposite type of video from the rest of the frame. If the CRC check is not valid the last character will be displayed in color. Data frames generated by an application program in HDLC mode will begin with a flag and end with the two byte CRC and a closing flag. Idle line fill is selectable between steady MARK (all '1's) and flags. Application programs can also generate frames with no CRC and frames ending with an abort.

9.2 IDLE
This menu selects the idle line fill between frames generated by an application program. The Comscope can generate FLAG characters or constant MARK ('1's) between the data frames.

9.3 DATA CODING
The Comscope can monitor or generate data transmitted as Non-Return-to-Zero (NRZ, the normal method) or Non-Return-to-Zero-Inverted (NRZI.) NRZI data may be clocked using the external clocks (NRZIc) or the Comscope can derive the clock using a Phase Locked Loop (NRZId). If you select NRZId you must select the normal bit rate of the data in 9.6 below.

9.4 BITS/CHAR
This menu selects the number of bits in each character between the opening flag and the two CRC bytes (flag and CRC characters are always 8 bits.) If less than eight bits per character is selected the unused upper bit(s) will be displayed as 0s.

9.5 CODE
The Comscope will display the names of all the code translation filed (files with .OM5 extension) in the current directory. Select the name corresponding to the coding of the data you are monitoring. Note that you can switch between hexadecimal and the selected code while monitoring or scrolling through data (Sections 12.5 and 13.15.) Data generated by an application program will be translated to the selected code as listed in the tables in the APPLICATIONS manual.

9.6 SPEED
This menu selects the nominal bit rate when monitoring or generating NRZId coded data (9.3 above.) For all other modes this menu selects the bit rate of the clock that will be generated by the Comscope when used with a DCE type adapter.

9.7 JOURNAL
The Comscope allows you to save a copy of captured data to a disk file for later analysis. See Section 7.7 above.

10.0 UNKNOWN SUB MENU

This screen is entered by depressing ENTER with UNKNOWN selected in the MODE menu (section 5.1.) This screen has six menus, SPEED, BITS/CHAR, CODE, DATA, ORDER, and JOURNAL, and eight function keys. The functions of the eight function keys are described in section 6 above.

10.1 General Information
The UNKNOWN mode provides the maximum amount of information when the type of data transfer on a channel is unknown. The unknown mode merely shifts in the specified number of bits and displays them as one character. You can either use the line clocks or set the Comscope to generate its own internal clock which will sample the two data leads at the specified bit rate. An application may also generate data in unknown mode.

10.2 Speed
Select the internal clock rate to be used or select EXT to use the line clock. If send or receive data is not displayed with EXT selected it indicates that the appropriate clock is not present. Selecting one of the other rates sets the Comscope to sample the data leads with its own internal clock, at the specified number of bits/second. You can also enter a rate not shown by entering the decimal value at the ">" prompt. The rate must be an integral multiple of the system clock as explained in Section 7.2 above.

10.3 Bits/Char
This menu selects the number of bits that will be assembled and displayed as one character. If less than 8 bits per character are selected the unused upper bit(s) will be 0s.

10.4 Code
The Comscope will display the names of all the code translation files (files with .OM5 extension) in the current directory. Select the name corresponding to the coding of the data you are monitoring. Note that you can switch between hexadecimal and the selected code while monitoring or scrolling through data (Sections 12.5 and 13.15.)

In this mode data codes are likely to produce garbage since there is no character synchronization. However, you may want to use one of these codes with the bit scroll keys in the scroll mode (Section 13.10) to help identify valid data. You can return to this menu and load a different code then re-display the data in that code by hitting F3.

10.5 Data
This menu selects whether the data is normal or invented polarity. See the page for the electrical interface adapter you are using to identify what normal polarity is. You can change this option when scrolling through captured data to help identify whether data is normal or reverse polarity. Leave scroll mode (Section 13) with function key F2, select the opposite polarity at this menu, then re-enter scroll mode by hitting function key F3.

10.6 Order
This menu selects whether data is transmitted least significant or most significant bit first. You can change this option when scrolling through captured data to help identify whether the data was transmitted least or most significant bit first. Leave scroll mode (section 13) with function key F3.

10.7 Journal
The Comscope allows you to save a copy of the data you are monitoring to a disk file for later analysis. See Section 7.6 above.

11.0 SEARCH MENU

This screen is entered by depressing F6. This screen consists of four function keys and up to four menus. With this screen you do not select the menus with the left and right arrow keys; they are brought up as needed by the Comscope for additional information. You use the up and down arrow keys as usual to select a trap item from the left menu. Depressing the ENTER key will bring up a menu in the middle of the screen if more sub-options exist. The selected trap item will then appear in the 'menu' at the right, which is really only a list. You scroll through or change this list. You can only add to it or hit function key F6 to erase the list.

11.1 General Information
The search menu allows you to specify a sequence of events for the Comscope to search for. In live mode, you may either highlight data or stop capture when the sequence is found. If you select 'stop capture; the Comscope will stop capture and enter captured mode (section 13) with the cursor positioned after the search sequence. When a search sequence is in effect there will be a 'S' on the second line from the bottom of the live mode display (see diagram at 12.0). The search menu may also be called from captured mode (Section 13.16). In this case the Comscope will search the capture buffer or the specified sequence and put the cursor immediately following the last element of the sequence. If the sequence is not found the cursor will be at the end of the buffer and the 'S' indicator will be on. Each sequence may consist of up to 16 'events' as described below.

Setting up a search sequence is generally an intuitive process, but you should be aware of exactly how the Comscope processes search consequences. The foreground part of the Comscope reads entries out of the capture buffer and displays them on the screen. As it is doing so it compares the entries to the search sequence. If an entry matches the first item in the search sequence the Comscope will then begin comparing with the second item in the sequence, and so on until the last item in the sequence has been found. Certain conditions will cause the Comscope to reset the sequence, that is, go back and start searching for the first event again.

If the next item in the search sequence is a data character and a different data character is found in the buffer the sequence will be reset. Note that the Comscope differentiates between transmit and receive: If the Comscope is searching for a transmit data character it will not reset on a receive character.

If the next item in the search sequence is a control lead turning "ON" or "OFF" and the opposite change is found the sequence will be reset. Note that you can only search for control leads changing, since this is the only time an entry is made in the buffer. Also, control lead capture must be ON in order to search for control lead changes.

If the next item in the search sequence is the beginning or end of a break or abort and the opposite (beginning instead of end or vice versa) is found the sequence will be reset.

If the next item in the search sequence is the end of a good or a bad frame in HDLC mode and the opposite end of frame (bad instead of good or vice versa) is found the sequence will be reset.

A search is 'set' when you leave this menu. Once the search sequence is found the search is disabled but the search remains in memory. You can re-enable the search by calling the search menu and then exiting it (i.e. hit F6 then F2.)

11.2 Control Leads
RTS, CTS, DTR, DSR, CD, and RI. Selecting one of these control leads will bring up an option menu requiring you to select ON or OFF or ANY CHANGE. Select whether you want the search condition to be the selected lead turning on or off or either.

11.3 End Of Frame
End of frame is only defined in the HDLC mode. Selecting end of frame will bring up an option menu requiring you to select Transmit or Receive. Select whether you want the end of a transmit or a receive frame. The Comscope will then bring up another option menu requiring you to select Good CRC, Bad CRC, or Any Frame. Select either a good frame, an errored frame or either one. An aborted frame must be selected via 11.4 below.

11.4 Break/Abort
Break is only defined in asynchronous mode and abort is only defined in HDLC mode. Selecting break/abort will bring up an option menu requiring you to select Transmit or Receive. Select whether you want a transmit or receive break or abort. The Comscope will then bring up another option menu requiring you to select START or END. You must select whether you want to trap on the beginning or end of the break or abort. The end of an abort in this case refers to the first 0 after an abort. This may also be useful on lines with idle mark.

11.5 Parity Error
Parity is only defined in asynchronous mode. Selecting parity error will bring up an option menu requiring you to select Transmit or Receive. Select whether you want to trap on a transmit or receive parity error.

11.6 Framing Error
Framing error is only defined in asynchronous mode. Select framing error will bring up an option menu requiring you to select Transmit or Receive. Select whether you want to trap on a transmit or receive framing error.

11.7 Tx Data
This option selects valid transmit data characters. The display line in the right hand menu will contain four elements when this selection is complete. The first is the mnemonic 'Tx DATA.' The second is the hexadecimal value of the character. The third, in single quotes, is the character representation, mainly for text, and the fourth is the hexadecimal value of the mask. The mask value is 'AND'ed with the received data before comparing with the character being searched for. This allows you to eliminate the parity bit or only look for certain bits within a character.

Selecting Transmit data brings up an option menu requiring you to enter the value of the character to trap on. The top option within this menu allows you to press the key corresponding to the character you want to trap on. The key code is translated according to the table in the translation code file you are using (section 6.) The code you are using must be set before you use this option. The mask value will be set according to the number of bits per character selected. If parity is selected the high order bit will be masked out.

Selecting the second line of this menu allows you to enter the hexadecimal value of the character to trap on. Entering a value will overlay the FF that is displayed on this line. The Comscope will bring up a second option menu which requires you to enter the hexadecimal value of the data mask. This option selects valid received data characters. The format is the same as 11.7 above.

11.9 Sync Sequence
Synchronization is only defined for the synchronous mode (see section 8.) Selecting this option will bring up an option menu requiring you to select either transmit or receive. Select whether you want to trap on a transmit or receive synchronization sequence being detected.

11.10 When Found….
This option selects the action to take when the selected sequence is found. When you hit ENTER the Comscope will bring up an option menu with the following five options:
11.10.1 Delay
This option instructs the Comscope to delay the specified number of events before taking any further action. Selecting this option will bring up an option menu requiring you to enter the decimal value of the delay you wish. The delay can be in the range of 1 to 32000. An event can be any one listed in 11.1 above or a time stamp which can take up 1 to 4 event locations.
11.10.2 Highlight On
This option will cause all succeeding data to be highlighted. This option has no effect in captured mode. Other search events may follow "Highlight on.' 'Highlight on' is often used with highlight off' and 'Search again' below to highlight a string of data.
11.10.3 Highlight Off
This option will cause all succeeding data to be displayed normally.
11.10.4 Stop Capture
This option will cause the Comscope to stop data capture and jump to Review Captured Data mode (Section 13) when the search sequence is found. The Comscope defaults to 'stop capture' if 'search again' below is not specified at the end of a sequence.
11.10.5 Search Again
This option will cause the Comscope to reset the search sequence, i.e. to go back and begin searching for the first item in the search sequence again. This is normally used with 'highlight on' and 'highlight off.'

11.11 Trap Menu Function Keys
11.11.1 F2 - Return from Search Menu
Depressing function key F2 will return you to where you were when you called the search menu. If you called the search menu from Review Captured Data mode (section 13) the Comscope will search the capture buffer for the selected sequence, positioning the cursor after the next occurrence of the sequence or the end of the buffer if not found. If you called the search menu from the other menus the selected sequence will be enabled for when you begin Viewing Live Data (Section 12.)
11.11.2 F6 - Clear Search Sequence
Depressing function key F6 key will erase whatever search sequence may have been selected. F6 is the only way to 'edit' a search sequence or to cancel one once selected.
11.11.3 F10 - Exit Program
Depressing function key F10 will exit the Comscope program and return to DOS.

12.0 VIEW DATA LINE ACTIVITY

12.1 General Information
In live mode data is captured and displayed on the screen. The display is full duplex. There are really 7 rows (11 in EGA mode) of display data: A transmit data character on top and the corresponding receive character beneath it. If there is no corresponding transmit or receive character the space will be blank. The states of the control leads are displayed on the bottom row. See section 2 for the meaning of these leads. At the left of the row immediately above this is a reminder that function key F1 will bring up a brief help screen. To the right of this is the name of the transaction code file which indicates the coding of the data, such as ASCII or IPARS. To the right of this are indications of whether journalling, a search sequence, or an application program are in effect. A 'J' indicates data is being journalled to a file, an 'S' indicated that a search sequence is in effect, and an 'A' indicates that an application is in control. If either of these conditions is not in effect there will be a dot in the appropriate location.

If an application program is active there may be less lines of display data than described above, or none at all. An application may or may not support the function keys described below. The documentation for the application will detail this.

There are seven actions that can be taken in live mode, accessed via the function keys as described below.

12.2 F1 - Help
Depressing function key F1 will bring up a menu describing the functions of the seven function keys described here and the meanings of various elements of the live mode display. Note that data is accumulating in the capture buffer and cannot be displayed while you are viewing the help screen. If you spend too long in the help screen the buffer may overflow, stopping data accumulation. The screen is thus intended only for a quick reminder.

12.3 F2 - Return
Depressing F2 will halt data capture and display and return you to the screen from which you entered live mode.

12.4 F3 - Enter Scroll Mode
Depressing F3 will cause the Comscope to stop data capture and display and enter captured mode (section 13).

12.5 F4 - Toggle Display Code
Depressing F4 changes the display from the selected data code to hexadecimal or back again.

12.6 F6 - Define A Search Sequence
Depressing F6 will take you to the search menu (section 11). Note that data is accumulating in the capture buffer and cannot be displayed until you return from the search menu. If you spend too long in the search menu the buffer may overflow, stopping data accumulation. Calling the search menu from live mode is thus not recommended except in situations with little data activity.

12.7 F10 - Exit Program
As at all places in the Comscope program, depressing F10 terminates the program and returns to DOS.

13.0 REVIEW CAPTURED DATA

13.1 General Information
Captured mode allows a detailed analysis and viewing of data captured in live mode. It may be entered from live mode or when examining a journal file. The captured mode screen is very similar to the monitor mode screen with the following additions:

at the bottom right hand of the screen you will see four two-digit numbers. This is the time stamp in hours, minutes, seconds, and 1/100 seconds. If time stamping was not enabled (see 5.9) then the time will not change and will be the time when capture started.

at the right of the second line from the bottom will be a brief explanation of the current entry in the capture buffer. The cursor is always immediately to the right of the current data. Entries in the buffer may be data or other events: To view the exact chronological order move the cursor to the left of the data in question, then use the right arrow key repeatedly and read the explanation line for each keystroke. You are actually stepping through the buffer one entry at a time.

the arrow keys at the right of the keyboard enable you to move through the data. Note that in scrolling through the data the Comscope is designed so you never lose your place. The cursor can only be moved to data already displayed on the screen. If, for instance, you want to move a whole screen (or 'page') at a time your first keystroke moves the cursor to the upper left hand corner and the next keystroke moves that data to the lower right hand corner. While this may slow down your rate of movement through the buffer somewhat, it makes it much easier to keep track of the relationship of various data.

13.2 Home
The home key will display the first page of data in the buffer. If the buffer is full it may take several moments for the Comscope to get back to the beginning of the buffer.

13.3 End
The end key will display the last page of data in the buffer. If the buffer is full it may take several moments for the Comscope to get to the end of the buffer.

13.4 Pgup
The page up key moves the cursor back one screen at a time. If the cursor is in the upper left hand corner the data will be scrolled down one row, if not, the cursor will be moved to the lower left hand corner.

13.5 Pgdn
The page down key moves the cursor ahead one screen at a time. If the cursor is in the lower right hand corner the data will be scrolled to the upper left corner, if not, the cursor will be moved to the lower right corner.

13.6 Up Arrow
The up arrow moves the cursor back one row at a time. If the cursor is at the top row the screen will be scrolled down one row, if not, the cursor will be moved up one row.

13.7 Down Arrow
The down arrow key moves the cursor ahead one row. If the cursor is in the bottom row the screen will be scrolled up one row, if not, the cursor will be moved down one row.

13.8 Left Arrow
The left arrow key moves back one entry in the buffer. It does not necessarily move the cursor. The new entry will be identified on the second line from the bottom and the time or control lead indications will be updated if appropriate.

13.9 Right Arrow
The right arrow key moves ahead one entry in the buffer. It does not necessarily move the cursor. The new entry will be identified on the second line from the bottom and the time or control lead indications will be updated if appropriate.

13.10 Shift-Left Arrow
Pressing the shift key and the left arrow key when viewing data captured in the UNKNOWN mode shifts the character boundary by one bit. The low order bit of the previous character (the one to the left) becomes the high order bit. Since there is no character synchronization in UNKNOWN mode the character boundaries are arbitrary. This key may be useful in identifying the format of unknown protocols. Bit shifting the data until clear text or some recognized pattern is seen often helps identify the data.

13.11 Shift-Right Arrow
Pressing the shift key and the left arrow key when viewing data captured in the UNKNOWN mode shifts the character boundary by one bit. The low order bit of the previous character (the one to the left). See 13.10 above (shift left).

13.12 Captured Mode Function Keys
There are four function keys that can be used in the captured data mode.

13.13 F1 - Help
Depressing F1 will bring up a help screen describing the function keys and scroll keys that can be used in capture mode.

13.14 F2 - Return
Depressing F2 will return you to where you were when you entered captured data mode.

13.15 F4 - Toggle Display Code
Depressing F4 will change the display form the selected data code to hexadecimal or back again.

13.16 Shift F4 - Print Captured Data
Holding down the shift key and hitting function key F4 will bring up a print menu, which will allow you to print a copy of data in the capture buffer. See section 14.

13.17 F6 - Define A Search Sequence
Depressing F6 will bring up the search menu (section 11) which will allow you to enter a sequence to search for in the capture buffer. After hitting function key F2 in the search menu the Comscope will begin searching from the current cursor position until the desired sequence or the end of the buffer is reached. The Comscope will display a screen of data with the end of the sequence at the lower right hand corner of the screen. If the sequence is not found the 'S' indicator will be on, otherwise it will be a dot.

Note that the Comscope searches from the current cursor position. Scroll mode is entered with the cursor at the end of the data buffer, so you must get to the beginning of the buffer, or before the area to be searched, usually with the Home key.

13.18 F10 - Exit Program
As at every point in the Comscope program, depressing F10 will terminate the Comscope program and return to DOS.


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