4 wire Lease line V23 modem
V23 modulation explained

V.23 modem Analog 4-Wire lease Line Synchronous/Asynchronous Modem

V.23 Full duplex 600 or 1200 bps Asynchronous or synchronous RS-232 V.24 4-wire, full duplex line application Standalone and rack mount High stability transmit and receive frequency Ruggedized and full temperature range Fully compatible with V.23 modems DIP switch setting no AT commands

The V.23 modem operates at 600 and 1200 bps, synchronous or synchronous, with V.23 modulation. It accepts external transmit clock on pin 24 of the DTE connector or generates internal clock. It is now available in a full 13.5" PC ISA card, 7.25" half card size, and standalone configuration. The pc card uses the internal PC ISA bus only for power from the pc bus. The phone line connector is an RJ-11 for 4-wire leased line operation. Standard leased line wiring with transmit is on positions 2 and 3, receive 1 and 4 of the 4 position RJ-11 connector.

The modem has a push/push switch for local digital loop on or off. The DIP switch is located on the PC card and is accessible behind the front panel of the standalone modem. The loop-back switch is located on the rear of the unit, next to the DB-25 terminal connector.

• V23 Analog full duplex, 4-wire, 600 ohm balanced
• Frequency Shift Keying:
  Mark-1300 hertz at 600 & 1200 bps, Space-1700 hertz at 600 bps, 2100 hertz at 1200 bps
• Transmit and Receive clock supplied by modem, Modem supplies transmit clock and recovered received clock, allowing the modem to run sync or async without a switch
• Transmit level control from +3 dBm to -30 dBm, (+3, 0 -16 and -30)
• The modem operates with no errors when signal interruptions occur at less than ¼ of a bit length (300 microseconds) at the selected bit rate
• Operates with no errors when the signal level changes up to 25 dBm
• Will drive up to 30 Km of cable depending upon wire gauge
• Switched carrier or constant carrier operation (RTS forced on or terminal controlled)
• The modem operates with no errors when signal interruptions occur at less than 1/4 of a bit length (300 microseconds) at the selected bit rate
• The modem operates with no errors when the signal level changes up to 25 dBm /UL> Digital Interface
  • RS-232/V.24, DB-25S
  • Signals are Tx, Rx, RTS, CTS, DSR, DCD,TxClock, RxClock, Ext TxClock
  • RTS/CTS delay is 4 or 8 ms in switched carrier mode or RTS can be forced on
  • Rx data is clamped to mark when no receive carrier detect is present.
  • Rx clock continues to run when carrier detect is off

  Controls and Indicators

  • Power, Tx Data, Rx Data, RTS, CTS, DCD, Test
  • Digital loop via rear panel switch and front DIP switch
  • Controlled carrier (with RTS/CTS delay) or constant carrier with RTS/CTS on
  • Rts/CTS delay of 4 or 8 ms
  • Loopback or normal operation
  • Internal timing or external transmit timing
  • Synchronous speeds of 600 or 1200 bps
  • Transmit levels + 3 dbm, 0 dbm, -16dbm, or -30 dbm

  Physical and Electrical

  • -40C to +70C operating temperature range, PC ISA bus format or standalone version,
  • PC bus for power and ground only, standard standalone unit uses 120V wall mount supply
  • Half size PC ISA card, 7.25"D x 4.25"H
  • Stand alone: 5.5" W x 7.375"D x 1.5" high, 120VAC wall mount supply (9VDC, 500 ma)
  • Other DC power supply voltages, 12, 24, -48, 125 VDC, available on special order
  • A 1.5" x 19" fixture is available to rackmount up to 3 standalones in a single 1U height
  • 20 slot rack chassis on slide guides is 19"W x 16"D x 7"H, 110VAC 250 W power supply

  Switches

  DIP SWITCH SETTINGS 
  Switch                        DOWN                        UP
  1 - N/A
  2 - Speed                      600                        1200        
  3 - RTS/CTS delay        4 ms                        8 ms
  4 - Carroer                  Constant                RTS Controlled         
  5 - Clocking                Internal                External Pin 24 input        
  6 - Transmit Level        See table
  7 - Transmit Level        See table
  8 - Digital Loop           Loop On                        Loop Off

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  racks

  20 slot rack chassis - 19"W x 16"D x 7"H	Standalone rack fixture - 18.95" x 1.75" high Single, Triple Unit Rack Mounts

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  V23-SA	V.23 Modem - Standalone
  V23-R	V.23 Modem - Rackmount
  20S Rack	20 Slot Rack w/ power supply
  1U Rack	Rack mount 1 unit wide
  1U Rack-3	Rack mount 3 units wide

see other modem pages