Section 365-001-201
5
Table 1. Notes for Figure 3
#
Note
#
Note
1.
Connector
13.
XMT input range at tip and ring: +7 dBm to –7.5 dBm. The unit is
factory adjusted for 0 dBm input. The XMT ATTEN is set for 9.5
dB attenuation.
2.
Primary transmission path
14.
RCV output range at tip and ring: +6 dBm to –10.5 dBm. The
unit is factory adjusted for –3 dBm output. The RCV ATTEN is
set for 9.0 dB attenuation.
3.
PC mount test point
15.
Models:
3650–01 900 ohm w/LC
3650–03 600 ohm w/LC
4.
Signal flow direction
16.
The level at the transmit unbalanced monitor points TX–TXR.
Measured with a bridged meter, should be +5.2 dBm +/–0.1 dB.
5.
N.O., N.C. relay contacts
17.
The XMT ATTEN provides 16.5 dB attenuation in 0.1 dB steps
to accommodate input range of from +7 dBm to –9.5 dBm. With
–9.5 dBm input, no attenuation is needed. When input goes up,
an appropriate amount of attenuation is added so that the level
at TX–TXR is maintained at +/–5.2 dBm to +0.1 dB.
6.
Front panel marking
18.
The RCV ATTEN provides 16.5 dB attenuation in 0.1 dB steps to
accommodate output range of from +6 dBm to –10.5 dBm. With 6
dBm output, no attenuation is needed. An appropriate amount of
attenuation is added when a lower output level is required.
7.
Optional circuit enclosure
19.
A91–369000/03 PBN/BOC are ordered separately and used when
inserted into connector J3. Open option A when PBN/BOC is used.
8.
Receptacle type, optional strap
Alternate position
20.
A91–369100 nonloaded cable equalizer or a A91–369101 loaded
cable equalizer is ordered separately to provide post-equalization
when inserted into connector J2, and pre-equalization when in-
serted into connector J4.
9.
Open, closed screw option
21.
For full 8-bit conversion, open screw options XC (encoding) and
YC (decoding). For 7 5/6 bit encoding and to send a busy to the
far end on both signaling highways close option XC. Similarly,
for 7 5/6 bit decoding, close option YC.
10.
Coil type test point
22.
Screw options AC, BC and JC are used to provide sealing cur-
rent.
Close Option
Open Option
Function
AC, BC
JC
Supply sealing current to the
loop.
JC
AC, BC
Complete the path when seal-
ing current is supplied from the
far end of the loop.
11.
Ganged switches are indicated by dashed connection line or
suffixed reference designation.
23.
The trunk processing relay (TP) is activated immediately upon
an alarm condition in the channel bank. Approximately 2 sec-
onds later it is deactivated for 70 milliseconds During the acti
12.
PC mount test jacks:
onds later it is deactivated for 70 milliseconds. During the acti-
vated mode, leads designated as 1 and 2 are shorted. Lead 2
Marking
Function
vated mode, leads designated as 1 and 2 are shorted. Lead 2
can be grounded by screw option Y. When the channel unit is
removed from the mounting slot, the “1” lead (pin 2) is con-
T&R Line (J1–A)
Access towards channel unit
removed from the mounting slot, the “1” lead (pin 2) is con-
nected to ground through a shorting contact in the backplane
card connector
T&R drop (J1–B)
Access towards office equip-
ment
g
g
g
card connector.
TX&TXR (TP3 & TP4)
4-wire XMT monitor
4.2
Receive VF Path
Digital data on the RDATA lead is read into the decoder, which provides digital-to-analog conversion.
The output of the decoder is applied to the RCV filter. The RCV filter reconstructs the transmitted waveform from
the stair-step output of the decoder and suppresses frequencies above 4kHz.
From the RCV filter, signals pass to the RCV ATTEN circuit, which is adjusted to provide the required output level
at the 2-wire pair. Adjustment is accomplished via push-on jumpers which provide up to 16.5 dB attenuation in 0.1
dB increments. The output of the RCV ATTEN is forwarded to the EQL AMP. The EQL AMP, in conjunction with
an optional equalizer subassembly, provides amplitude pre-equalization for nonloaded or loaded cable.
The output of the EQL AMP is applied through the 2W/4W hybrid to transformer T1 and to tip and ring (pins 48
and 50).
