Port Sharing With Multiple Hosts - GE MDS SD Series Reference Manual

In such a system, each RTU gets every message from the host computer,
and the underlying protocol (e.g., Modbus, DNP, etc.) must sort out
which messages are applicable to a specific RTU.
Ethernet Data Port Menu
MASTER RADIO
To Ethernet Port
HOST COMPUTER
TCP Ethernet
(Host A)
Key Multihost Settings:
Multihost Delay, No. of Ports, IP Address,
Port No., Multihost Time-Out
REMOTE RADIO
REMOTE RADIO
(One of several possible sites)
(One of several possible sites)
SERIAL RTU
SERIAL RTU
SERIAL RTU
SERIAL RTU
Figure 8. Serial Remotes with Two Serial Ports

Port Sharing with Multiple Hosts

The transceiver allows for several external data networks to use the
same RF network without confusing the data streams. This is known as
"Multihost" operation, and it requires that the radio be operating in
Packet Mode.
In such a system, multiple host computers at the Master Unit poll their
respective RTUs, which may be alone or co-located at the Remote sites.
Figure 9 shows an example of such a system. In this case, two host com-
puters (Host A and Host B) are connected to the Master Unit via the
applicable data ports.
MDS 05-4846A01, Rev. C SD Series Ref. Manual (Packet & Transparent Mode) 11