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Short Range Modems PCM2D/PCM2L

Discontinued, recommended replacement is: PCM2/M


Short Range Modem PCM2D/PCM2L Features:
  • Up to 2.5 km
  • G.703 2.048 Mbps line interface
  • Full duplex synchronous mode
  • Data interface: Ethernet 10/100Base-T or V.35/RS-530/RS-449/RS-232
  • Selectable data rates
  • Async mode for RS-232
  • Digital, remote and line loopbacks
  • Integrated BER tester
  • Dry contacts alarm interface (PCM2D only)
  • Stand-alone or rack-mount (PCM2L: stand-alone only)
  • AC or DC power
  • Certificate N OS/1-SPD-694 of Russian Ministry of Communications

The PCM2 is a high speed short range modem connecting synchronous DTEs such as routers or computers over two twisted pairs or two coaxial cables of up to 2.5 km. With G.703 (2048 kbps) as a line interface it operates at six selectable data rates, from 64 kbps to 2048 kbps.

On the digital side, a choice of V.35, RS-232, RS-530, multi-standard or Ethernet interface is available.
The multi-standard interface supports V.35, RS-530, RS-232 and X.21 standards. User has the flexibility to change the interface type by changing only the interface cable. V.35 interface has the standard M34 female connector.
Pair of modems with Ethernet interface forms the remote bridge to connect LANs.

The PCM2D modem is available as a stand-alone unit or as a card for 19'' 3U high Cronyx rack.

The PCM2L modem is low-cost modification of the PCM2 modem. The difference between PCM2L and PCM2D versions is as follows:

  • PCM2L uses DB15 connector type on G.703 interface (PCM2D modem has terminal block).
  • PCM2L has no alarm interface.
  • PCM2L is available as a stand-alone unit only.

PCM2D setup is performed by microswitches on the bottom cover of the unit. Front panel buttons control all diagnostics options including loopbacks and BER testing.

Stand-alone models may be ordered with 220VAC or 36 to 72VDC power supply.


G.703 Interface (2048 kbps)
Connector Type (for PCM2D modem) Terminal Block
Connector Type (for PCM2L modem) DB15
Line Code HDB3
Line Impedance 120 Ohm Balanced (Twisted Pair) or 75 Ohm Unbalanced (Coax Cable), Switches selectable
Receive Signal Attenuation Range from 0 to 43 dB (up to 2.6 km of 22 AWG twisted-pair cable)
Transmit Timing Sources INT (Internal Oscillator), RCV (Receiver), EXT (Digital Interface)
Jitter Attenuator In both the receive and the transmit paths, 120UIpp attenuation
Error Detection Bipolar Violation
Digital Interface
Data Transfer Rate 2048,1024, 512, 256, 128, or 64 kbps
Async data rates 1.2, 2.4, 4.8, 9.6, 19.2, 38.4, 57.6, 115.2 kbps
Async symbol formats 8N1, 8P1, 8N2, 7P2, 7P1
Clock Options Supported TXC, RXC, ETC
Modem Control Signals Supported DTR, DSR, CTS, RTS, CD
Interface Ethernet
Interface 10/100Base-T
Connector Type RJ-45 (female)
Data Transfer Rate 2048,1024, 512, 256, 128, or 64 kbps
Mode 100 Mbps Full-duplex,
100 Mbps Half-duplex,
10 Mbps Full-duplex,
10 Mbps Half-duplex,
or Autonegotiation
Address table size 15000 MAC addresses
Maximum packet size 4224 bytes, including MAC header
Protocols Transparent or Cisco-HDLC bridging IEEE protocol, automatically selected
Quality of Service 8 priority levels
Alarm Interface (for PCM2D modem only)
Connector Type 6 Pins Mini-DIN
Relay Contact Current up to 250 ma
Relay Contact Voltage up to 175 VDC
Loopbacks Digital, Remote and Line Loops
BER Tester Activated by pushbutton


Some of the documents are in Adobe® Acrobat® Reader® format

PDF  User's Manual for models PCM2D and PCM2L with Ethernet 10/100Base-T interface, in Russian
PDF  For devices since 01/06/2007: User's Manual for models with PCM2D and PCM2L with V.35/RS-530/RS-232/X.21 interface, in Russian
PDF  For devices before 01/06/2007: User's Manual for models with PCM2D and PCM2L with V.35/RS-530/RS-232/X.21 interface, in Russian
PDF  Cronyx interface cables guide

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