Specifications

2-4
Reference Guide
Model No.
Running Head
Voice Modules and Applications Applications
2.3.3 E&M Card
This integrated access system supports two variants of E&M cards:
•
8108 E&M Card supports eight 2-wire E&M or Transmission Only (TO) ports
•
8119 E&M Card supports eight 4-wire E&M or Transmission Only (TO) ports
The 8119 E&M card offers an extended Transmit TLP range (-17.5 to +14.5dB) to better
support dedicated 4-wire modem applications. This may be required in situations when
specific types of modems being connected to the ports cannot, or will not, change their output
power levels. Modems can only be connected with the E&M when placed in TO mode.
E&M cards can be installed in any of the User Slots of the system chassis. E&M cards encode
the incoming analog voice signals into 64 Kbps PCM format before transmission onto the
network. Each E&M card provides a single 50-pin female AMPHENOL connector (RJ27X).
All three cards support E&M signaling types I, II, IV, and V.
Most port parameters are software configurable on a port by port basis including the Mode of
each port ("E&M", "E&MR2" or "TO"). The PCM Coding to be used is either u-law, a-law or
a-inv (for inverted a-law). The Trunk Conditioning (busy or idle) is configured on the
equipment in case the WAN facility that the port is connected fails.
The user may also specify, on a port-by-port basis, whether to use North American ANSI
standard default, ABCD signaling, or ITU (CCITT) ABCD signaling by turning the signaling
conversion setting "on" or "off".
For the Model 8108 2-wire E&M card only, the trans-hybrid balance may be specified as one
of eight values as well as for a customized user-specified terminating impedance ("user"). All
eight values are identical and are set for a terminating impedance of 900_@2.15µF.
Software-initiated testing and diagnostics supported on E&M cards include the setting of both
analog and digital loop backs towards the network and the generation of a Digital MilliWatt
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 E and M leads of any 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. Table 13 shows how the
E&M cards can use the voice-compression features of the ADPCM resource card.