ZyXEL Communications Multi-service Access Platform MSAP2000 - Manual (Page 162)

7. Product Specification
MSAP2000 Technical Manual V3.0 7-55
7.20. 2W/4W Ear and Mouth Module (2W/4W E&M)
Overview
The 2W/4W Ear and Mouth Module (2W/4W E&M) are 2-wire and 4-wire
E&M subscriber channel cards, which comply ITU-T G.712 standards.
The dipswitch on the Module board can be used select either a 2-wire or
4-wire setting, for the analog interface of each E&M channel. 2W/4W
E&M supports TYPE V and Transmit Only (TO) modes. In a CAS
Signal Transmission System, all E&M signals in the 2W/4W interface
are coded and imbedded as “a”, “b”, “c”, “d” bits into the corresponding
E1 Digital Signal Timeslot (slot 16). Undefined “a”, “b”, “c”, “d” bits are
coded according to sequence, as “1”, “1”, “0”, “1”.
Features
And
Benefits
„ Panel LEDS indicate status, faults, alarms, and network connections.
„ Loop status detection and Signaling exchange
„ A-law or u-law compounding
„ New Voice CODER design
„ TYPE V or TO Mode, selectable by software
„ Alarm and Fault monitoring and reporting
„ Timeslot assignment for Voice Services
„ Use of non-volatile memory devices for performance data storage
Function Diagram
Application
The E&M are most used for tie-line or transmission only (TO) application
for PABX or VF leased line..
OIM/
SM1/
SM4
E&M OIM/
SM1/
SM4
QE1M
PSTN Switch
E&M E&M
PABX
TO mode
Modem
TO mode
Modem