Connecting To Electrical Intermicom; Short Distance; Long Distance; Figure 167: Direct Connection - GE P4A Technical Manual

P54A/B/C/E
6

CONNECTING TO ELECTRICAL INTERMICOM

Electrical InterMiCOM uses EIA(RS)232 communication presented on a 9-pin 'D' type connector. The connector is
labelled SK5 and is located at the bottom of the 2nd Rear communication board. The port is configured as
standard DTE (Data Terminating Equipment).
6.1

SHORT DISTANCE

EIA(RS)232 is suitable for short distance connections only - less than 15m. Where this limitation is not a problem,
direct connection between devices is possible. For this case, inter-device connections should be made as shown
below the figure below.
E02522

Figure 167: Direct connection

For direct connection, the maximum baud rate can generally be used.
6.2

LONG DISTANCE

EIA(RS)232 is suitable for short distance connections only - less than 15m. Where this limitation is a problem, direct
connection between devices is not possible. For this case, inter-device connections should be made as shown
below the figure below.
IED
DCD
RxD
TxD
DTR
GND
RTS
E02523

Figure 168: Indirect connection using modems

This type of connection should be used when connecting to devices that have the ability to control the DCD line.
The baud rate should be chosen to be suitable for the communications network. If the Modem does not support
the DCD function, the DCD terminal on the IED should be connected to the DTR terminal.
P54xMED-TM-EN-1
IED
1
DCD
2
RxD
3
TxD
4
DTR
5
GND
6
7
RTS
8
9
Modem
1
DCD
2
RxD
TxD
3
4
GND
5
6
7
8
9
Chapter 16 - Electrical Teleprotection
1
2
3
4
5
6
7
8
9
Modem
DCD
RxD
Communication
TxD
Network
GND
IED
DCD
RxD
TxD
DTR
GND
RTS
IED
1
DCD
RxD
2
TxD
3
DTR
4
GND
5
6
RTS
7
8
9
337