Tellabs 6461 Quick Start Manual

Ytellabs
technical manual
76-816461
rev B
practice section 816461
©
Tellabs Inc., 2 September 1979
all rights reserved, printed in USA
6461 Common Signaling Module (2W/4W)
page 1
page 2
page 3
page 5
page 7
page 6
page 6
contents
section 1 general description
section 2
application
section 3 installation
section 4 circuit description
section 5 functional schematic
section 6 specifications
section 7 testing and troubleshooting
1. general description
1.01 The 6461 Common Signaling Module (fig-
ure 1) provides transmission interface between a
4wire facility and 2wire or 4wire telephone station
equ ipment or a PBX trunk. Both adjustable transmis-
sion attenuation and switch-selectable 4wire-to-
2wire conversion are provided. As an alternative to
2wire-to-4wire conversion, the6461 may be switch-
optioned to provide a 4wire-to-4wire pad/transfor-
mer interface. In addition, the 6461 accepts several
types of optional signaling converter plug-on sub-
assemblies that provide various modes of loop-to-E
and M signaling conversion.
1.02 Levels in both transmit and receive channels
may be prescription-set via front-panel switches that
introduce from
a
to 32.5dB of attenuation, in
0.1 dB increments, into the transmit and receive
4wi re paths.
1.03 An integral two-coil hybrid provides 4wire-
to-2wire conversion of the transmission facility. A
switch option, however, conditions the 6461 to
provide 4wire transmission on both the terminal
side and the facility side. The 4wire terminal-side
option provides adjustable transmission attenuation
and transformer isolation and balance.
1.04 Switchable 600 or 900 ohm terminating
impedance is provided on the terminal side of the
6461 when the module is optioned for 2wire loop
operation. Terminal-side terminating impedance is
fixed at 600 ohms when the module is optioned
for 4wire loop operation. The 600 or 900 ohm re-
sistive component at the 2wire port is in series
with a 2.1511F capacitive component. On the fa-
cility side of the 6461, terminating impedances are
fixed at 600 ohms.
1.05 The 6461 module is designed to accept
Tellabs' series of 9961X loop-to-E and M Signaling
Converter plug-on subassemblies. The 9961A sub-
assembly, when used on the 6461, provides con-
version between E and M signaling over the 4wire
facility and foreign exchange station-end (FXS)
loop signaling. The 9961 B subassembly provides
conversion between E and M signaling and foreign-
exchange office-end (FXO) loop signaling. The
page
1
figure 1. 6461 Common Signaling Module
9961C subassembly provides conversion between
E and M signaling and switchboard (ac) or manual
(dc) ringdown loop signaling. Signaling conversion
is provided when the 6461 is optioned for either
2wire or 4wire loop operation. For complete in-
formation on the 9961 X subassemblies, refer to the
separate Tellabs Practices on these subassemblies.
1.06 The 6461 is equipped with a compromise
balance network that provides 600 or 900 ohm
impedance in series with 2.1511 F capacitance when
the module is optioned for 2wire loop operation.
Network build-out (NBO) capacitors associated
with this balance network provide from
a
to
0.12611 F of NBO capacitance in 0.00211F in-
crements. If precision balancing of the hybrid is
desired, a Tellabs 993X Precision Balance Network
(PBN) subassembly may be plugged into a receptacle
on the 6461 's printed circuit board and the com-
promise network switch-optioned out of the
circuit. Refer to the 993X Tellabs Practice for
detailed information on these PBN subassemblies.
1.07 The front panel of the 6461 contains, in
addition to the aforementioned attenuation
switches, two light-emitting diodes (LED's) that
light to indicate seizure in either direction (i.e., to
indicate E-Iead and M-Iead status).
1.08 When used without an associated 9961 X
Signaling Converter subassembly, the 6461 module
is completely passive except for its front-panel
LED's and thus requires no external power connec-
tions unless it is desired that these LED's be func-
tional. Because the 9961X subassemblies are active