49018-0697 <90-00089>
P
AGE
5
49018
STATION
SELECTOR
SUBASSEMBLY
NOTE:
All connections to the 44020
Decoder outputs are made
directly through the J1/P1
and J2/P2 connectors
44020
HOST MODULE
POWER-UP
BUSY IN
POWER-UP
CLEAN IN
RESET IN
RING
GENERATOR
START
CLEAN OUT
BUSY OUT
DIGIT 1 OUT
DIGIT 0 OUT
CKT 2 OUT
CKT 1 OUT
P2-3
P2-4
P2-5
P2-6
P2-7
P2-10
P2-11
3
4
5
6
7
10
11
P2-8
P2-9
P2-12
P1-10
P1-12
-10
VDC
P1-1
P1-2
P1-3
P1-4
P1-5
STROBE
A
B
C
D
8
9
12
F
IG
. 2 - 49018 S
UBASSEMBLY
-T
O
-H
OST
M
ODULE
P
IN
C
ONNECTIONS
The strobe pulse also advances the digit counter which counts
up to three digits. Additionally, the strobe pulse initiates a clock
pulse output from the clock pulse delay circuit to gate the
station address latches. During the digit count, selected by the
digit strap option, the address in the address buffer latch is
compared to the preset address code selected by the miniature
10-digit switches. If the code matches, the matching station
address latch is not set and the corresponding station drivers
(1 or 2) output (P2-3 or P2-4) is enabled (grounded).
The last digit, whether the digit strapping is a one, two, or
three-digit code, will inhibit additional clock oulses from enter-
ing the digit counter. When a station driver is enabled, the
corresponding front panel LED will light.
The busy control output can be activated internally or exter-
nally. This circuit provides a ground output at P2-7 that can be
used to apply a busy tone to a subscriber phone or outside line.
The busy output can be activated internally when a *, #, or
A BCD input (depending on strapping) is decoded. The busy
output can also be activated by an external Power-up Busy
input at P2-12.
CIRCUIT DESCRIPTION