Specifications

Chapter 4 4-Wire E&M/TO Configuration
4-1
4-WIRE E&M/TO CONFIGURATION
ABOUT THIS SECTION
This section describes how to configure the 4-wire E&M/Transmission Only (E&M/TO) 12-channel voice
card for connecting the Access Bank I to T1 private line services that support E&M signaling types I, II,
IV and V. Also, cable information and specifications are provided at the end of this section.
4-WIRE E&M/TO VOICE CARD
Functional Description
The 4-wire E&M/Transmission Only (E&M/TO) voice card delivers 12 analog channels for connecting to
private line circuits, such as carrier PBX tie lines and 4-wire modems often found in utility, cellular, and
metropolitan area networks (MANs). Each of the twelve E&M channels can be individually programmed
to support Signaling Types I, II, IV or V, using up to 4 signaling and transmission pairs per channel
(E/M, SG/SB, T/R, and T1/R1). This card can be configured to function as Channel Equipment (normal
multiplexer mode) or as Switching Equipment for back-to-back Tandem applications sometimes referred
to as Reverse E&M or Pulse Link Repeater (PLR).
Physical Description
Like the FXS and FXO/DPT voice cards, the 4-wire E&M/TO is a 7.8” by 13.16” daughter card designed
to slide into the back of the Access Bank I along rails that guide a 64-pin DIN connector to mate with a
matched connector on the internal ABII Controller. The E&M/TO card receives T1 signaling, control
logic, and -48 Vdc power through this connector from the Controller card. Because the RJ-21X
Amphenol  Telco connector on the ABII front Control Panel fails to provide enough wiring leads, it is
bypassed through a 96-pin E&M signaling line connector attached on the opposite end of the card. The
E&M signaling lines (E, SG, M, SB, T, R, T1 and R1) are connected to this high-density 96-pin DIN
connector. A bank of 12 channel status LEDs are located next to the E&M signaling line connector on the
ABII back plate. Each channel has two programming jumpers that allow the channel to be configured for
E&M Types I, II, IV and V signaling. Each channel also has a 10-position DIP switch that allows the
receive and transmit attenuation to be individually set from -22 dB to +10 dB. There is also a 4-position
DIP switch located next to the processor for setting regular or clear channel E&M signaling types and
selecting busy or idle during carrier failure.
TYPICAL APPLICATIONS
The major applications for the 4-wire E&M/TO voice card are E&M Tie Lines operating in either Normal
or Tandem mode. Additionally, this interface also supports two-way Direct Inward Dial (DID)