Trunk Access Equipment; 110-Bi -25 Or 700A-66-B1-25 Cut-Down Jack; Emergency Transfer Unit (Etu) - AT&T Network Adapter 25 Installation And Maintenance Manual

INSTALLATION
Access
Trunk Equipment
The trunk access equipment (TAE) consists of 700A-I 10-61-25 or 700A-66-
B1 -25 (157BF) cut-down jacks, or equivalent, and up to four 10B Emergency
Transfer Units (ETUs). The 10B ETU is shown in Figure 2-1.
700A- 110-M-25 or 700A-66-B1-25 (157BF) Cut-Down Jack
Trunk circuits that appear on the network interfaces are grouped by trunk
type (Direct Inward Dialing [DID], Central Office [CO], or Tie) and punched
down on the 700A jack. One 700A jack is required for each RJ21 X or RJ2GX
network interface. The 700A-1 10-B1-25 jack has a 110-type cut-down field,
and the 700A-66-B1-25 (157BF) has a 66-type cut-down field. It is important
to note that most secondary wiring protectors (sneak current fuses) are
compatible only with the 66-type jack.
10B Emergency Transfer Unit (ETU)
During a power failure or system outage, each 10B ETU provides contact
closures for bypassing the switch and connecting up to five predesignated
FCC registered single-line voice terminals to telephone company trunks.
Connectorized cables (25-pair) connect the ETU to the 700A jacks, the
system cabinets, and the Station Interconnect Panel. A modular plug-ended
cord (part of octopus cable) connects control power (–48 V dc) from the
system cabinet.
Screw terminals that connect to relay contacts which may be used for an
external alerting device are also provided. The relay contacts close when a
failure occurs. (Any alerting device and associated power unit with a dc
current requirement less than or equal to 0.5 ampere may be used.) The ETU
also controls a DID make-busy contact that connects to the last pair on the
700A jack. For a more detailed drawing of the 10B ETU, see Install
Emergency Transfer Units (ETUs) in this part.
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