Section 365-001-201
3
number is advanced by 1 and imprinted on subsequent units manufactured. Therefore, be sure to include both
the model number and its issue number when making inquiries about the equipment.
2.3
Static Concerns
Each module is shipped in static-protective packaging to prevent electrostatic charges from damaging static-sen-
sitive devices. Use approved static-preventive measures, such as static-conductive wrist straps and a static-dissi-
pative mat, when handling modules outside of their protective packaging. A module intended for future use should
be tested as soon as possible and returned to its original protective packaging for storage.
Do not ship or store modules near strong electrostatic, electromagnetic, or magnetic fields. Use the
original static-protective packaging for shipping or storage.
CAUTION
3.
APPLICATION GUIDELINES
The 3650-01/03 channel units provide a voice path without signaling. Typical applications are for private line data
services requiring a metallic facility extension, tandem circuits employing inband signaling such as SF circuits,
and other applications where voice transmission without signaling is required. See Figure 2 for a typical applica-
tion.
360/363
D4
T
E
R
M
I
N
A
L
2W ETO
3650-
01/03
STATION
EQUIP-
MENT
TCXR Facility
+6 to –10.5 dBm
METALLIC FACILITY
–9.5 to +7 dBm
Figure 2. 3650–01/03 2W ETO w/LC Channel Unit Typical Application
4.
CIRCUIT DESCRIPTION
Refer to the block diagram in Figure 3 while reading the following circuit description.
4.1
Transmit VF Path
VF signals applied to the input tip and ring leads (pins 50 and 48) are routed through the DROP and LINE break-
ing jacks to transformer T1. In turn, transformer T1 provides DC isolation from the metallic facility and accepts
input signals from –9.5 to +7 dBm. After passing through the 2W/4W hybrid, the VF signals are routed to the XMT
AMP. This circuit amplifies the signal to compensate for losses in the transformer and filters.
From the XMT AMP, signals pass to the XMT ATTEN circuit, which is adjusted to provide the proper signal level
to the encoder. Adjustment is accomplished via push-on jumpers which provide up to 16.5 dB attenuation in 0.1
dB increments. The output of the XMT ATTEN is forwarded to the EQL AMP. The EQL AMP, in conjunction with
an optional equalizer subassembly, provides amplitude post-equalization for non-loaded or loaded cable.
The adjusted VF signal is then applied to the XMT filter, which suppresses frequencies outside the bandwidth of
the standard voice frequency and prevents them from entering the encoder.
The filtered VF signal is then applied to the encoder. Access to the signals at the encoder input is provided by
jacks TX and TXR. The nominal level at this point it +5.2 +/–0.1 dBm (measured with a 600-ohm bridged meter).
During the encode command pulse on the ECM lead, analog signals present at the input of the encoder are con-
verted to digital signals. The digital data stored in the encoder is transmitted on the XDATA lead.
