Motorola V186 - Cell Phone - GSM System Planner Manual page 136

The FEP in the system illustrated above serves as a network node between link RADIO 1
and link LINE 1. Configuring the FEP to have access to two different links enables it to
serve as a node between these links. The MDLC protocol permits RTU-to-RTU
communications without the intervention of the central computer. RTUs that are not on
the same link communicate with each other via the network node (in this case, the FEP).
A multi-link system is a network that uses several link types. The following figure
illustrates a system where a third link type, RS232, connects an RTU to another terminal
that communicates over RADIO 2. RTUs connected to the IP link can reach RTU 7 via
IP network and then RADIO 2.
Central
Computer
RS232
Two-Zone System
A two-zone system that uses conventional radio over a single frequency is described in
the following figure:
ZONE 1
RTU 2
FEP
Store & Forward
FEP
RTU 1
RTU 3
132
IP
RADIO 2
RS232
RTU 7
RTU 9
ZONE 2
RTU 4
Communications
RTU 5
RTU 6