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  DMM-4DC 4 Port, RS-232 Buffered Sharing Device, -48VDC for TELCO applications

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The RS-232 Digital Mixing Module (DMM-4DC) or port sharing device is a network expansion device for modem sharing or port sharing applications in polled or contention environments. The DMM-4DC allows up to four devices to share a modem / DSU or computer port. The port contention modes are RTS, DCD or switch on Data. Any combination of terminals and modems may be used in a network environment. Each port of the DMM-4DC may be selected as a DCE or DTE interface. Once installed, system and network efficiency are increased through higher host processor utilization coupled with the significant decrease in idle time between host / terminal traffic sessions.


  • Ordering Information
  • Specifications
  • Features & Benefits

Technical Specifications for the V.35 Digital Sharing Device:

Part Number Model Description
162000 DMM-4DC RS-232 Digital Mixing Module

Warranty Three Years, Return To Factory
Included with each unit: 1) Operations Manual
2) U.S.A. Grounded Power Cord, Part # 713015
3) Optional Power Cords
  • A) United Kingdom, Part # 713016
  • B) Continental Europe, Part # 713017
  • C) Other: Specify Country on Purchase Order OPTIONAL ACCESSORIES

1) Spare Data Center Fuses
  • A) 160ma Fuse, Qty (2) Part # 714000
  • B) 80ma Fuse, Qty (2) Part # 714001

Technical Specifications for the DMM-4DC, -48V DC POWER:

Application Multiple Sync/Async DCE/DTE devices operating in a polled or contention environment, to share one DCE/DTE port
Main Input: One RS-232 Port Subchannel Ports: One to Four RS-232 Sync/Async devices Main Input: One RS-232 Port Subchannel Ports: One to Four RS-232 Sync/Async devices
Interface EIA RS-232-D, CCITT V.24 using DB-25 female connectors, selectable as DCE or DTE interface
Data Format Data transparent at all data rates
Data Rates Internal Select: 450bps to 76.8Kbps External: Up to 128Kbps
Timing Options Internal External: via Input Master Port External: Telco Timing via Port 1
Anti-Streaming Automatic: Selectable time-out intervals Disable: Selectable via dip switch
Terminal Service Modes Sequential scanning for RTS or DCD control signal, option for switch on RXD Data(JP6-JP9)
Clear To Send Allows normal RTS/CTS handshaking or has option for Forced CTS on Ports 1-4 (JP1-JP4)
RTS To CTS Delay Selectable RTS to CTS delays of 0, 5, 10 and 20ms
Front Panel Indicators: Power, Transmit Data, Receive Data, Channel Active, Channel Stream Switches: Enable/Disable of each Sub-channel
Power Source DC Voltage, Input Range of -36 to -72vdc Current Draw at 48vdc: 75ma @ 3.6watts
Regulatory Approvals Tested According to UL 60950-1:2003, CAN/CSA-C22.2 No. 60950-1:2003 CE Safety EN60950 and CE EMC EN300-386-2
MTBF 315,419 Telecordia Issue 1
Environmental Operating Temperature: 32º to 122º F (0º to 50º C) Relative Humidity: 5 to 95% Non-Condensing Altitude: 0 to 10,000 feet
Dimensions DMM-4DC Height: 1.75 inches (4.44 cm) Width: 17.00 inches (43.18 cm) Length: 9.00 inches (22.86 cm)
Weight 4.5 pounds (2.1Kg)

Features & Benefits for the DMM-4DC:

* RS-232 Port Sharing Device
* Interface - EIA RS-232, CCITT V.24, DB-25 Female Connectors
* Data Rates - Synchronous or Asynchronous to 128Kbps
* Anti-Streaming - Automatic or Manual for unattended Circuit Restoral
* DCE/DTE Selectable
* Tail Circuit Buffer
* Supports CSU/DSU's, LL Modems, Dial Modems and Terminals
* RTS/CTS delays options
* Transparent to Data
* Fully Cascadable
* Internal or External Clocking
* Sturdy Metal Rackmount Enclosure
* -36 to -72 DC Input


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