4.24
Intercom is factory-wired, requiring the 424C
(Fig. 13), 456B (Fig. 18), and 460B (Fig. 20)
KTUs furnished with the 570A KSU. See Fig. 31
for KTU locations in the KSU. The intercom code
of a station is determined by the column on
connecting blocks 3, 4, or 5 on which the station
cable is terminated. See 3.05(8) and Fig. 26.
5101 1SU
0G O G B G B B 0 B B
ISS 3, SECTION 5 1 8-450- 1 00
will ring at station 3 and the second CO/PBX will
ring at station 16.
B. External Signaling Circuit
4.27
Where external signaling devices (such as
bells, gongs, chimes, lights or buzzers) are
to be connected to the 7 A System, a 22A -49
apparatus unit must be provided.
The 22A-49
apparatus unit is externally mounted and connections
are made to the KSU with inside wire. Also, an
external power supply must be provided to operate
the signaling devices. The 22A-49 apparatus unit
may be used to activate external signaling devices
that are operated by an open circuit (through a
relay break con tact) or that are opera ted by a
circuit closure (through a relay make contact).
Caution:
The 22A-49 appara tus unit
contains a nonadjustable, mercury-wetted,
sealed contact relay and must be mounted
in a vertical upright position.
4.28
The 22A-49 apparatus unit is used to activate
external signaling devices that are connected
Fig. 3 1 -Location of 424C, 4568, and 4608 KTUs,
for:
2-Path Intercom
OPTIONAL FEATURES
A. CO Ringing
4.25
The CO ringing feature permits a station
not wired for common audible to receive
the ringing signal on a selected CO/PBX line. Any
combination of stations may be connected for CO
ringing on a one line per station basis.
Remember:
The CO ringing is tone ringing.
4.26
A terminal representing each CO/PBX line
is brought out on connecting block 1, row
21 (see Fig. 32).
To connect CO ringing, on
connecting block 1, column C, select the terminal
associated with station to ring on a particular
CO/PBX line. Then run a strap (RC-) from the
station terminal in column C to the particular CO
ring terminal in row 21. See Fig. 32. Fig. 32
illustrates station 3 strapped (RC-1) to the CO ring
terminal (in row 21) of CO/PBX line 1 and station
16 strapped (RC-2) to the CO ring terminal of
CO/PBX line 2. In this instance, CO/PBX line 1
•
Station codes (See Fig. 33)
•
Common audible (See Fig. 34)
•
CO/PBX ringing (See Fig. 34)
•
Ring transfer (See Fig. 34).
4.29
One 22A-49 apparatus unit is required for
each station code or each CO/PBX line
equipped with an external signaling device.
Connections for station codes are shown in Fig. 33.
Connections for common audible, CO ringing and
ring transfer are shown in Fig. 34. The maximum
resistance of each lead between the KSU and the
22A-49 apparatus unit is 25 ohms.
4.30
The KS-16301 type auxiliary signals are
recommended as external signaling devices
for use with the 7A System.
See Fig. 35 for
connections.
Refer to Section 463-110-100 for
identification, installation, operation, maintenance,
and ordering information on the KS-16301 type
signals.
4.3 1
The external power supply used to operate
the signaling devices must be properly fused
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