1.0 General Description

To satisfy the requirement for a rack mounted RS-232 to EIA-530 converter, Telebyte developed the Model 267-X. These rack mounted devices provide conversion for the entire interface which provides 10 Category I circuits and three Category II circuits and are fully compatible with Telebyte's Model 62-1/7 and -2/8 RS-232 to EIA-530 standalone converters. The 267-1/3 includes an RS-232 port to be interfacedto a DTE whereas the 267-2/4 has an RS-232 port for a DCE.

The EIA-530 port on the Models 267-1/2 comply with the signal characteristics of MIL-STD-188-114A, Type II, while the Models 267-3/4 comply with MIL-STD-188-144 Type 1.

2.0 Specifications

The Models 267-1 through -4 have several common features, specifically:

Size: 7"L x 1"W x 6.25"H

Environment: 0° to 50° C, 5 to 95% RH (no condensation)

Data Rate:
0 to 500KBPS for 267-1/2
0-100KBPS for 267-3/4

Power: Power is supplied to the units from the 76-6 Card Cage.

Connector: The DB-25 connector types for the Models 267-1 and 267-2 are described below.

76-6 Card Cage

Note: The Models 267-3/4 require a Model 76-6-291 Card Cage.

The type refers to the configuration of that port on the converter. For example, the RS-232 portof the Model 267-1 is a Female DB-25 connector, that is configured as a DCE to be interfaced to a DTE.

3.0 Interface Descriptions

The Models 267-1/3 and 267-2/4 differ in the type of RS-232 port which is being interfaced. The 267-1/3 is designed to interface to a RS-232 port configured as a DTE, thus, converting it to an EIA-530 DTE port. The Model 267-2/4 is designed to convert a RS-232 DCE port into an EIA-530 DCE port.

Table 1 indicates the direction and phase of the converted signals. The Category I circuits of the EIA-530 interface are electrically equivalent to RS-422 for 267-1-2 and MIL-STD-188-114 Type 1 for the 267-3/4. All types use a differential protocol signalling technique on the EIA-530 side. Of the two EIA signals associated with a circuit, the one referred to as the A signal is denoted with a plus sign, i.e. TD+. The standard polarity of this signal is the same as its associated RS-232 signal. If TD is low then TD+ is negative with respect to TD-. If TD is high then TD+ is positive with respect to TD-. The B signal, denoted by a negative sign, normally is at the level opposite its associated RS-232 signal. The Category II signals are single ended circuits. The polarity of these EIA-530 signals are normally the same as their associated RS-232 signal, unless a jumper has been positioned to invert the phase. When referring to Table 1 note that an arrow facing right (>) indicates a signal that is converted from an RS-232 signal to an EIA-530 signal and an arrow facing left (<) indicates a conversion from EIA-530 to RS-232. A single star (*) indicates that pin 1 of J1 is connected to pin 1 of J2 and can be disconnected by removing a shunt. A double star (**) indicates that pin 7 of both connectors are common.

The phase of the signals associated with pins 2, 3, 18, 21, and 25 are jumper selectable.

There is a similarity between the RS-232 specification and the military specification MIL-STD-188C. The specifications differ in that the voltage range for the military specification is +/-6V. Secondly, MIL-STD-188C calls for wave shaping and Models 267-1/2 have no wave shaping on the output signals. Finally, the specifications define the phase of the data signals differently. RS-232 defines a mark as a negative voltage whereas MIL-STD-188C defines it as a positive voltage. To accept MIL-STD-188C signals jumpers have been provided on the data signals. To convert from RS-232 to MIL-STD-188C data signals change jumper JP 12 and JP 14 from the factory set positions to the inverted positions. Refer to Section 3.2.1 for a further explanation of phasing the data signals.

The Models 267-1/2 will interface properly with MIL-STD-188C devices although these previously mentioned provisions should be considered.

3.1 Connector Pinouts

Table 1: Model 267 Converter Pin-Outs
For the units to begin transmitting RTS and DTR must both be asserted.

3.2 User Selectable Options

The Model 267-1/2 is designed with a number of user selectable options that affect the relative phase of input and output signals. Those signals that have user selectable phasing are the data signals, TD and RD, and loop control signals LL, RL, and TM. There is also a jumper which allows the connection of pin 1 of both connectors. This jumper position is JP-1 for 267-1/2 and JP-7 for 267-3/4. Removing the shunt disconnects pin 1 of J1 from pin 1 of J2. The factory setting is for the shunt to be installed.

As shown on the block diagrams there are A and B signals associated with each category I circuit. The marking condition, a binary "one," is when the A signal is at a lower voltage then the B signal. The normal phase of the category II circuits has marking associated with a voltage that is negative with respect to a spacing condition. All signals that are not jumper selectable adhere to these normal phasing rules, as do the factory settings of the jumper shunts.

To adjust the jumpers from their factory set positions, turn the power switch off. Remove the card from the 76-6 Card Cage. Locate the jumpers to be changed and refer to the following sections for changing the phase.

3.2.1 Data Signal Phasing for Model 267-X

The data phase selection shunts are described on the following table. This table shows the shunt positions required for normal and inverted phasing of the signals. Both of these jumpers are on the PC board.

Table 2: Selecting Relative Phase of Data Signals
3.2.2 Control Signal Phasing for Model 267-1/3

The phase of the LL (J1 pin 18, J2 pin 18), TM (J1 pin 25, J2 pin 25) and RL (J1 pin 21, J2 pin 21) signals for the Model 267-1 are affected by the shunts located at jumpers JP4, 5, & 6. For the Model 267-3 use jumpers JP6 and JP8. The shunts allow user selection of the phase signal on pin 18 and 21 of the EIA-530 interface as well as selecting the source of those signals. There are two EIA-530 driving circuits involved with these signals. The normal configuration of the converter associates pin 18 of each connector with each other as well as pin 21 of each connector with each other.

Refer to the block diagram of the 267-1 to determine operation in other than the factory set configurations.

Table 3
3.2.3 Control Signal Phasing for the Model 267-2/4

Signals LL, RL and TM for the Model 267-2 are affected by JP4, 5, and 6 while the Model 267-4 are affected by JP6, 8, and 7.

The factory setting for the LL, RL, and TM signals is for normal phasing. Refer to the Model 267-2 block diagram for other configurations.

The TM signal is factory set for normal phasing.

Table 4
4.0 Block Diagram Model 267-1/3

5.0 Block Diagram Model 267-2/4

6.0 Help

If any assistance is required call Bomara Associates at (800)-5BOMARA or (978)-452-2299.
Technical Support E-Mail: bobr@bomara.com
or use our Online Contact Form

Document No. 0315-0117
Rev. A

Warranty

Telebyte warrants the equipment to be free from defects in material and workmanship, under normal and proper use and in its unmodified condition, for 12 months, starting on the date it is delivered for use. TELEBYTE's sole obligation under this warranty shall be to furnish parts and labor for the repair or replacement of products found by TELEBYTE to be defective in material or workmanship during the warranty period. Warranty repairs will be performed at the point of manufacture. Equipment approved for return for warranty service shall be returned F.O.B. TELEBYTE factory and will be redelivered by TELEBYTE freight prepaid, except for non- continental U.S.A. locations. These deliveries will be sent COD freight and import/export charges.

THE ABOVE WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, STATUTORY OR OTHERWISE, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TELEBYTE SHALL NOT BE LIABLE FOR ANY DAMAGES SUSTAINED BY RESELLER OR ANY OTHER PARTY ARISING FROM OR RELATING TO ANY EQUIPMENT FAILURE, INCLUDING, BUT NOT LIMITED TO CONSEQUENTIAL DAMAGES NOR SHALL TELEBYTE HAVE ANY LIABILITY FOR DELAYS IN REPLACEMENT OR REPAIR OF EQUIPMENT.

Out of warranty equipment may be returned to the Greenlawn, NY customer service facility prepaid as described above. Return shipping charges will be billed to the customer. The repaired unit will have a 90 day warranty. In those cases where "NO TROUBLE" is found, a reduced charge will be billed to cover handling, testing and packaging.

Model 267-3/4