2-2
IMACS System Release 5.1.9
Reference Guide
Model No.
Running Head
Voice Modules
Applications
2.2
Voice Modules
2.2.1
Foreign Exchange Station (FXS) Card (812960)
This Integrated Access System supports one variant of Foreign Exchange Station (FXS) cards:
•
812960 FXS Card provides eight 2-wire analog ports with a terminating impedance of
600 ohms.
FXS cards can be installed in any User Slot in the system chassis. FXS cards encode the
incoming analog voice signals into 64 Kbps PCM format before transmission onto the
network. Each FXS card provides a single 50-pin female AMPHENOL connector (RJ27X).
All port parameters are software configurable on a port by port basis. The Mode setting
specifies whether the port is to be used for standard Foreign Exchange Station, Foreign
Exchange Software Defined Network, Private Line Automatic Ringdown (PLAR), or Dial
Pulse Origination applications. For example in the case of a PLAR circuit, the port can be
programmed to provide Ringback Tone towards the caller. The Type setting specifies Loop
Start, Loop Forward, Ground Start, Ground Start Immediate and Ground Start Automatic
operation. If the PLAR mode is selected, then the two options supported under Type are "D3"
and "D4" which meet the pre-1988 and post-1988 specifications for PLAR circuits. The PCM
Coding options supported include
µ
-Law, A-Law and inverted A-law, and the user may also
select the Trunk Conditioning mode (busy or idle) that should be applied towards the attached
equipment should the WAN facility that the port is connected to fails. In addition, both the
Transmit (Tx) and Receive (Rx) TLP levels can be set in increments of 0.1 dB. The Tx TLP
range is from -10.0 dB to +5.0 dB. The Rx TLP range is from -10.0 dB to +2.0 dB.
The user may also specify, on a port-by-port basis, whether to use North American ANSI
standard ABCD signaling (which is the default) or ITU (CCITT) ABCD signaling by turning
the signaling conversion setting "on" or "off". The trans-hybrid balance may be specified as
one of eight values as well as for a customized user-specified terminating impedance. At the
present time, all eight values are identical and are set for a terminating impedance of 600_@
2.15µF.
Software-initiated testing and diagnostics supported on FXS cards include the setting of both
analog and digital loopback towards the network and the generation of a Digital MilliWatt
(DMW) signal on a port-by-port basis. A robust set of test functions allow the user to monitor
and set the state of the analog Tip and Ring leads of any FXS port and to set and monitor the
state of the ABCD signaling bits of the digitized voice signal. In cross-connect systems, the
Test functionality also includes the ability to generate test tones (300Hz, 1 kHz, 3 kHz and
"quiet") and transmit those toward either the user side or the network side of the system. FXS
cards can use the voice-compression features of the ADPCM and LBRV resource cards.
