Siemens 7SG11 - Page 49

7SG11 Argus 8 Communication Interface
©2011 Siemens Protection Devices Limited Chapter 4 Page 8 of 8
Personal Computer
Personal Computer
Modem
PSTN : Public Switched Telephone Network
P
S
T
N
Modem
Modem
Serial optical link
Tx
Tx Tx
TxTx
Rx Rx
RxRx
Rx
SIGMA-4
Figure 5 - Optical Ring Configuration
Personal Computer
Serial optical
link
Tx Tx
TxTx
Rx Rx
RxRx
SIGMA-3
Local
RS232
System
RS232
Control System
Tx
Rx
FO
Figure 6 - Configuration using the Sigma 3 – Dual Port RS232 Device