ADTRAN Fractional T1 Tandem Channel Unit FT1-TDM - Manual

The ADTRAN FT1-TDM is a central office (CO) unit used to deploy Nx64
kbps tandeming between channel banks within a CO, where N is a selectable
number of channels ranging from 2 to 12. The FT1-TDM plugs directly into
a standard AT&T D4 (or equivalent) channel bank, or SLC-96 when running
SLC Mode 1 or 3 operation. The unit occupies a single slot. No installation
wiring is required. Signals are provided to and from the channel bank or RT,
while PCM signals are provided to the local CO loop.
One ten-position switch pack is used to configure the mode of operation
for the unit. Configuration is performed by manually selecting each option
switch.
Bandwidth is set by the FT1-TDM in contiguous or alternating time slots.
The front panel of the FT1-TDM contains DS0 splitting Bantam jacks.
The metallic splitting jacks provide an intrusive, signal-interrupting access
to the first DS0 channel. The Bantam jacks allow connection of a Tele-Path
Industries 108/109 RT II (or equivalent) test set through one DS0 channel
at 64 kbps for functions such as sending and receiving bit error rate signals,
and latching loopback sequences.
There are two loopbacks available to the FT1-TDM. NEAR loopback loops
the received T1 signal back to the T1 transmitter at the DSX-1 interface.
FAR loopback loops the received PCM data back to the PCM backplane.
NEAR loopback is a digital loopback toward the DSX-1 interface. This loop-
back is initiated by the DS0 latching loopback command or by the front
panel NEAR DIP switch. FAR is a digital loopback toward the PCM interface.
This loopback is initiated by the DS0 latching loopback command or by the
front panel FAR DIP switch. When the FT1 circuit is looped, all DS0s in use
will be looped back toward the PCM backplane and an all 1s signal will be
sent to the DSX-1 interface.
If needed, bi-directional tandem latching loopbacks are available by
looping a remote FT1-TDM and sending the sequence from a local unit.
The latching loopback sequence can also be initiated through the front
panel Bantam jacks.
P R O D U C T F E A T U R E S
■ Intra-office tandeming between
D4 channel banks
■ 12 DS0 capability
■ Multiple loopbacks and
diagnostics
■ Compatible with standard
AT&T D4
FT1-TDM
F R A C T I O N A L T 1 T A N D E M C H A N N E L U N I T