TO 1ST
CO/PBX
LINE
TO
2ND
CO/PBX
L1
NE
TO
3RO
CO/PBX
LI
N
E
TO 4TH
CO/PBX
LINE
TO 5TH
CO/PBX
LINE
TO 6TH
CO/PBX
LINE
TO 7TH
CO/PBX
L
I
N
E
Tl
Rl
T2
R
2
T
3
R3
T4
R
4
TS
RS
T6
R
6
T7
R7
P/0
CO
NN
0
I
4
5
3
4
3
2
23
I
I
3
3
452A KTU
K l
I
K 2
I
K l
6
K l
6
K 2
K 2
K 3
37
K 3
33
27
I
Kl
22
K 3
35
I
K 3
36
K 2
K2
I
P/0
CONN
ISS 3, SECTION 5 1 8-450- 1 00
EXT I
EXRI
EXT2
EXRZ
EXT3
EXR3
EXT4
EXR4
EXT5
EXR5
EXTS
EXR6
EXT7
EXR7
B BAT
B GRD
TO
I
ST
LINE
RINGER
TO 2ND
LINE
RINGER
TO
3RD
LINE
RINGER
TO
4TH
LINE
RINGER
T
O 5TH
LINE
RINGER
TO
6TH
LINE
RINGER
TO 7
T
H
LINE
RINGER
TO
POWER
SUPPLY
Fig. 1 6-Condensed Functional Schematic of 452A KTU (Power Failure Transfer Circuit)
I.
4608 KTU (2-Path Intercom Access Circuit)
2.26
The 460B KTU (Fig. 20) is an 8-inch unit
that contains two separate intercom paths.
Path selection is based on operation of the associated
intercom button on the key telephone sets. The
unit also provides dial tone, seizes the selector,
and provides a flashing lamp signal during selection
and a steady lamp during the busy mode. Control
circuitry permits only one intercom path to seize
the selector at a time.
J.
4788 KTU (TOUCH-TONE Adapter Circuit)
2.27
The 478B KTU (Fig. 21) is an 8-inch unit
that provides TOUCH-TONE dialing when
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