GE Power Management
ALPS Advanced Line Protection System
8-27
8 LOCAL USER INTERFACE
8.4 REMOTE COMMUNICATION INTERFACE
8
8.4.5 NULL-MODEM CONNECTIONS
A PC can be connected directly to the relay without a modem through a null-modem cable. The required pin-to-pin connec-
tions for the PC null-modem cable are shown below in Figure 8–4: 25-PIN NULL MODEM CABLE. The pin-to-pin connec-
tions for a null-modem cable to the 9-pin connector on the KEYPAD/DISPLAY INTERFACE are shown below in Figure 8–5:
NULL MODEM CABLE FOR PORT PL1. The null modem cable should be no more than 50 feet long.
Figure 8–4: 25-PIN NULL MODEM CABLE
Figure 8–5: NULL MODEM CABLE FOR PORT PL1
Table 8–6: MODEM COMMANDS FOR COMMUNICATION BETWEEN RELAY AND PC
FUNCTION
ALPS MODEM (REMOTE)
PC MODEM (LOCAL)
DTR Status
Follow DTR (&D3)
Follow DTR (&D3)
Result Code Format
Numeric (V0)
Numeric (V0)
Result Code Display
Disable (Q1)
Disable (Q1)
Command State Echo
Disable (E0)
Disable (E0)
Auto-Answer
Enable (S0=1)
Disable (S0=0)
Carrier Detect
Follow CD (&C1)
Follow CD (&C1)
Jack Type
RJ-11, etc. (&J0)
RJ-11, etc. (&J0)
Command Recognition
Disable (Dumb)
Enable (Smart)
Comm. Std. (@1200 bps)
Bell 212A (B1)
Bell 212A (B1)
Response to DTR
Ignore DTR (&D0)
Ignore DTR (&D0)
Fall Back to 4800Bd
AT#F1
Pulse Dial Ratio
39%Mk/61%Bk (&P0)
39%Mk/61%Bk (&P0)
2
7
20
22
6
8
5
4
3
7
20
22
6
8
5
4
3
2
TO RELAY
PL-2 & 3
TO PC
R E M O T E C O M M U N I C A T I O N S P C D I R E C T L Y
N U L L M O D E M C A B L E
G N D
D T R
RI
D S R
D C D
C T S
R T S
R D
T D
G N D
D T R
RI
D S R
D C D
C T S
R T S
R D
T D
2
5
1
8
7
4
9
6
3
5
1
8
7
4
9
6
3
2
TO RELAY
PL-1
TO PC
R E M O T E C O M M U N I C A T I O N S F R O M P L - 1 M O D U L E
N U L L M O D E M C A B L E
G N D
D C D
C T S
R T S
D T R
RI
D S R
R D
T D
G N D
D C D
C T S
R T S
D T R
RI
D S R
R D
T D