Description

FEATURES

• Full duplex rates to 1200 bps (in async V.23 mode)
• Asynchronous or synchronous RS-232
• 4-wire, full duplex line application
• Standalone or rack mount
• PC card rack mode (PC supplies power and ground only)
• High stability transmit and receive frequency
• Ruggedized for full temperature range application

DESCRIPTION

The Link1 TADILB modem operates at 600 and 1200 bps, synchronous or asynchronous, with V.23 modulation. The modem accepts external transmit clock on pin 24. The modem operates in Link1 DFSK mode (differential frequency shift key) at 600 and 1200 bps. Full 13.5” PC card, 7.25” half card size, and standalone configurations are available. The pc card uses the internal pc ISA bus only for power from the pc bus. The serial terminal interface is RS-232, DB-25. The phone line connector is an RJ-11 for 4-wire leased line operation. Transmit is on positions1 and 4, receive 2 and 3 of the 4 position RJ-11 connector.

The modem has DIP switch controls for the TADIL-B (V.23) or LINK1 mode, for 1200 or 600 bps operation, for 4 or 8 ms RTS/CTS delay, for constant carrier (RTS forced on) or terminal controlled RTS, and transmit level settings of +3, 0, -16 and –30 dBm. 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 loopback switch is located on the rear of the unit, next to the DB-25 terminal connector.

SPECIFICATIONS

Modem

• Analog full duplex
• 4-wire, 600 ohm balanced
• Frequency Shift Keying with the following logic:
  • Mark 1300 hertz at 600 and 1200 bps
  • Space 1700 hertz at 600 bps
  • 2100 hertz at 1200 bps
• DFSK. Differential Frequency Shift Keyed (Link1 mode)
• 600 and 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, implement as +3, 0 –16 and –30
• 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 dB
• The modem will drive a minimum of 100 meters of 26 AWG cable and will typically drive several kilometers of cable depending upon wire gauge. Line losses of up to 39 dB are normally acceptible for private line installations.
• Switched carrier or constant carrier operation (RTS forced on or terminal controlled)

Digital Interface

• RS-232, 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. In constant carrier mode RTS/CTS is forced on
• Rx data is clamped to mark when no receive carrier detect is present. Rx clock ontinues to run when carrier detect is off
• TxD, RxD, TxClock, RxClock signals may be inverted via jumper
• Ground Tie may be opened via jumper

Controls and Indicators

• Power, Tx Data, Rx Data, RTS, CTS, DCD, Test
• Power turns on when the modem is powered
• TxData and RxData LED’s light for RS232 SPACE condition
• RTS, CTS and DCD LED’s light for RS232 HIGH condition
• Digital loop via rear panel switch. Test LED lights during test. Loopback on when switch is pushed in, Loopback is off when switch is out
• Switch for mode, speeds, RTS control, RTS/CTS delay, clocking, transmit levels

Switches

• Controlled carrier (with RTS/CTS delay) or constant carrier with RTS/CTS on
• RTS/CTS delay of 4 or 8 ms
• Analog Loop or normal operation
• Internal timing or external transmits timing
• Synchronous speeds of 600 or 1200 bps
• Transmit level of +3 db, 0 db, -16db or -30db
• L1 (DFSK Mode) or TADILB (V.23 mode)

OPTION SWITCH SETTINGS

Transmit Audio Level Settings:

Internal Jumpers  for Signal Logic Inversion.  (near RS-232 connector)    
 

Physical and Electrical

• -35C to +70C operating temperature range
• PC ISA bus format or standalone version
• PC bus is used for power and ground only, standalone unit uses 110V wall mount supply
• Half size PC card, 7”D x 4.25”H
• Stand alone: 5.5” W x 7.375”D x 1.5” high, 110VAC wall mount supply
• Shipping weight: 5 pounds
• A 1.5” x 19” fixture is available for rackmounting up to 3 standalone units in a single 1U height
• 20 slot rack chassis is 19”W x 16”D x 7”H, 110VAC 250 W power supply
• Wall-mount power supply 120VAC

PC Card Rack Chassis

APPLICATION

The Link1 TADILB modem is normally used with standards based equipment that requires reliability rather than speed. The PC ISA format card is used in a standard PC ISA chassis.It draws power from that chassis and has no other internal chassis connections. There is a 20 slot ISA chassis available for this format with built-in power supply. The stand-alone model uses a wall-mount AC power supply. There is a 3 unit rack mount available for the stand-alone mldel.