Siemens 7SG11 Technical Manual page 49

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