P
AGE
4
44214-0898 <90-00005>
F
IG
. 1 - F
UNCTIONAL
S
CHEMATIC
; 44214 4-W
IRE
M
ODEM
CIRCUIT DESCRIPTION
UPDATED
TD
GROUND
35
17
ALB
DLB
MODE
DATA
RATE
RD
CTS
CD
RTS
DTR
S3
S5
+5
VDC
S2
I/O
GATING
&
DRIVERS
I/O
GATING
&
DRIVERS
I/O
GATING
&
DRIVERS
I/O
GATING
&
DRIVERS
MICRO
CONTROLLER
MODEM
CONTROLLER
NOTE: The following are accessible
through the front panel:
S1, S3, S4, S5, R44, R53
S4
+5VDC
JP4
JP5
RTS
DTR
INTERFACE
ENABLE
JP1
S6
T O
JP2
TTL /
CMOS
SIGNAL
GROUND
RS-232
RS-422
DTR
RTS
TD
RD
CD
CTS
DSR
TD
DTR
CTS
RTS
CD
RD
DSR
TX+
TX-
RTS+
RTS-
CD+
RX+
RX-
CD-
I/O
GATING
&
DRIVERS
REGULATED
POWER
SUPPLY
RX+
TX+
TX-
RX-
RS-485
-21 TO -56 VDC
+5 VDC
SOURCE
-12 VDC SOURCE
+12 VDC SOURCE
T O
JP3
RING
TIP
RING
TIP
4W XMT RCV
-or-
2W LINE
4W XMT
R44
R53
ANALOG
CIRCUIT
39
40
42
41
3
4
2
1
10
9
5
6
12
11
7
8
13
14
16
19
20
21
15
27
28
30
32
29
26
25
31
T O
RESET
S1
S7
2W/4W
47
ALB
DLB 45
