UniMod GSM-4
9
In the UniMod GSM-4 modem an additional slot is available for another in-
terface module. For this slot the following module types are available (instal-
lation: see page 32):
R T S
t m
C T S
t p
20mA
(CS, current loop) active (for 4 devices max.) or passive;
if the 20mA interface is active it must be operated either with a load or its
terminals must be short-cut.
R T S
t m
C T S
t p
RS232
(RxD, TxD, CTS, RTS, GND);
If RTS/CTS lines are used, the internal 20mA interface must be deactivated.
(Set jumper “RTS” and “CTS” instead of “tm” and “tp”.)
R T S
t m
C T S
t p
RS485
(2 wires);
R T S
t m
C T S
t p
RS485
(4 wires);
When the 4-wire interface is used, the internal 20mA interface must be de-
activate
d. (Set jumper “RTS” and “CTS” instead of “tm” and “tp”.)
R T S
t m
C T S
t p
M-Bus
active (for 10 devices max.) or passive;
Please note: All interfaces are internally connected with each other. Therefore all
attached devices receive the same data from the interface. It must be
ensured that never two or more devices send data at the same time.
Example demonstrating different kinds of connection:
