Tellabs 4406 KTU Technical Manual

7tellabs
technical manual
76-824406
rev B
practice section 824406
©Tellabs, Inc., 2 September 1982
all rights reserved, printed in USA
4406 KTU 4Wire Station Termination
figure
1.
4406 KTU 4Wire Station Termination
1.06 In addition to the transmit and receive
attenuator controls, the front panel of the 4406
contains a sidetone level control and four test
jacks, one at each port. All four are opening
ja~ks
facing the module. The front panel also contains
two LEDs, a red one that lights when the A relay
is activated and a yellow one that lights when the
PT relay is activated.
1.07 An internally regulated power supply in the
4406 permits operation on filtered, ground re-
ferenced -22 to -28Vdc input. Maximum current
requirement is 105mA plus loop current. Reverse-
battery and transient-limiting circuitry are pr.o-
vided in the module's internal power supply cir-
cuitry. Resistance-capacitance (RC) filtering and
decoupling networks minimize crosstalk coupling
and the effects of noise on the input power leads.
1.08 A Type 10 module, the 4406 mounts in
one position of a Tellabs Type 10 Mounting Shelf,
versions of which are available for relay-rack and
apparatus-case installation. I n relay-rack appl ica-
tions, up to 12 modules can be mounted across a
19-inch rack, and up to 14 modulescan be mounted
across a 23-inch rack. I n either case, 6 inches of
vertical rack space is used. The 4406 can also be
supplied as part of a self-contained 265A Voice Sig-
naling System for use in voice paging applications.
2. applications
2.01 The 4406 KTU 4Wire Station Termination
module provides a 4wire termination for a multi-
point voice network. The 4406 provides attenua-
tion talk battery, sidetone amplification, and trans-
for~er
isolation and balance for the station instru-
ment. Loudspeaker outputs are available for use in
page 1
contents
section
1
general description page 1
section 2 application page 1
section
3
installation page 2
section 4 circuit description page 4
section 5 block diagram page 5
section
6
specifications page 4
section
7
testing and troubleshooting page 6
1. general description
1.01 The 4406 KTU 4Wire Station Termination
module (figure 1) performs the functions required
to integrate a 4wire KTU station instrument into a
4wire voice network. The 4406 provides impedance
matching on the station side, contains pickup and
push-to-talk relays with auxiliary contacts for ac-
tivating lamps on the station instrument, and con-
tributes from 0 to 30dB of attenuation in both the
transmit and receive channels. A loudspeaker out-
put is available at the receive output port for .use
in voice-paging networks. The 4406 also provides
talk battery· and, optionally, sidetone to the
s~a­
tion. The 4406 does not directly interface a 4wlre
facility; a 4wire repeat coil, line amplifier, or other
line interface device must be used.
1.02 This practice section covers the Issue 2 ver-
sion of the 4406 module (Tellabs part number
824406). The Issue 2 4406 differs from the Issue 1
version through the addition of two LEDs to the
module's front panel. The practice is revised to
update the text portion of section 7.
1.03 On the station side, the 4406 provides a
switch-selectable terminating impedance of 1200,
600 or 150 ohms at the receive port and 600 or
900' ohms at the transmit port. On the facility side,
the 4406 provides a fixed terminating impedance
of 600 ohms at both the transmit and receive ports.
1.04 The pickup relay on the 4406 is activated
by the station instrument's A lead whenever the
station goes off hook. This completes the trans-
mission path and extends talk battery to the sta-
tion. The push-to-talk relay allows the 4406 to be
used with station instruments that are equipped
with a manual push-to-talk key and in radio-tele-
phone applications. Both relays provide auxiliary
contacts for control of lamps on the station instru-
ment. Contacts on the A relay mute the loudspeaker
output in voice-paging applications.
1.05 Variable attenuators on the 4406 provide
level coordination between the station and the fa-
cility-interface device. These attenuators can be
adjusted, via front-panel controls, to provide. from
o
to 30dB of attenuation in both the transmit and
receive channels (this is in addition to 0.5dB of
insertion loss).