PULSECOM 4TOLB-3L1 - Key Features of 4 TOLB-3 L1 Channel Unit; Applications of 4 TOLB-3 L1 Channel Unit

3
4TOLB-3L1
1306, Issue 2, May 1992
B. Features
The channel unit provides the following functional features:
•
4-wire voice-frequency (VF) transmission with DC isolation
•
Attenuation in the transmit (TRMT) and receive (RCV) paths selected with DIP
switches to compensate for variations in transmission levels
•
Front-panel maintenance-access connector (MAC) with bifurcated contacts
•
Loopback (LB) circuit with three-way LB activation: local, manual, or tone
•
Sealing current source/sink available with power-up ZAP (source mode)
•
Loopback gain/loss selectable from 0 to 31.75 dB in 0.25-dB steps
•
Can be used in the Pulsecom PD4 or PSC-96 channel bank
•
Can be used in the AT&T D4 or SLC 96 channel bank
•
Conductive front panel grounded to the frame
•
UL recognized
2. APPLICATIONS
The channel unit provides a 4-wire 600-ohm interface between a D4 or SLC 96 channel
bank and a 4-wire VF transmission facility with no DC signaling. An active loopback
circuit with an LB tone frequency of 2713 Hz is included. The LB circuit allows remote or
local testing of the 4-wire facility.
The unit can also be used on tandem carrier circuits utilizing end-to-end single-frequency
(SF) signaling. Figure 2 shows a typical application.
Figure 2. 4TOLB-3L1 Typical Application
T1
R1
T
R
DATA
STATION
TERMINATION
LB
X
F
M
R
RCV
ATTN
X
F
M
R
X
F
M
R
TRMT
ATTN
X
F
M
R
LB
G/L
LB
RELAY
LB
4TOLB-3L1
D4 CHANNEL BANK
T1
R1
T
R
DATA
STATION
TERMINATION
OFFICE A
D4
CHANNEL
BANK
OFFICE B
4ETO
T1
LINES
(1.544
MHz)
CUSTOMER
SITE