38
LDM-144LR
Appendix A: IR-G.703 Co-Directional
64-kbps Interface
IR-G.703 Co-Directional Interface
The IR-G.703 is an interface module for modems, converting G.703 co-
directional signals to TTL levels. The converted data is sent over the modem
link using the modem’s modulation technique and is converted back at the
other end into G.703 64-kbps co-directional signals, or any other possible
digital interface signals.
The module is available in two versions: for stand-alone modems and for
rack modems. The stand-alone version fits into a stand-alone modem, and is
available with two types of physical connections: terminal block or RJ-45. The
rack version mounts on the rack-version modem card, and uses the modem’s
edge connector for communication. The edge connector is wired on the
motherboard of the card cage to a DB25 connector on the back panel.
Figure A-1
illustrates the pinout of the different connectors.
NOTE
Rcv, in Figure A-1 refers to the input signals to the IR module, XMT refers
to the output signals from the module.
The approximate range between the IR G.703 module and the attached
G.703 equipment is up to 500 meters over 24 AWG cable (depending on
cable quality used).
The G.703 interface module has two operation modes, TX-FIFO and RX-
FIFO, which are strap-selectable on the board (see
Figure A-1
).
