GE LPS-O Instruction Manual page 198

8.4 REMOTE COMMUNICATION INTERFACE
sponds approximately to the 60 second delay (S7=60) at the PC modem; however, you should verify the
number of rings that correspond to 60 seconds for a particular application.
Table 8–6: MODEM COMMANDS FOR COMMUNICATION BETWEEN RELAY AND PC on page 8–31 lists
the modem command set required to communicate to the relay from a remote PC.
A PC can be connected directly to the relay without a modem through a null-modem cable. The required pin-to-
pin connections for the PC null-modem cable are shown in Figure 8–4: 25-PIN NULL MODEM CABLE. The
pin-to-pin connections for a null-modem cable to the 9-pin connector on the KEYPAD/DISPLAY INTERFACE
are shown in Figure 8–5: NULL MODEM CABLE FOR PORT PL1. The null modem cable should be no more
than 50 feet long.
T D 2
R D 3
R T S 4
C T S 5
D C D 8
D S R 6
RI 22
D T R 20
G N D 7
TO RELAY
PL-2 & 3
T D 2
R D 3
D S R 6
8
RI 9
D T R 4
R T S 7
C T S 8
D C D 1
G N D 5
TO RELAY
PL-1
8-
30
REMOTE COMMUNICATIONS PC DIRECTLY
N U L L M O D E M C A B L E
Figure 8–4: 25-PIN NULL MODEM CABLE
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
Figure 8–5: NULL MODEM CABLE FOR PORT PL1
LPS-O Line Protection System
8 LOCAL USER INTERFACE
8.4.5 NULL-MODEM CONNECTIONS
2
3
4
5
8
6
22
20
7
2
3
6
9
4
7
8
1
5
GE Power Management
T D
R D
R T S
C T S
D C D
D S R
RI
D T R
G N D
TO PC
T D
R D
D S R
RI
D T R
R T S
C T S
D C D
G N D
TO PC