RS232 <=> RTC<=> RS485
Modem
20
SOCOMEC - Réf. : 874 669 A GB
INSTALLATION
ON
1 2 3 4
ON
1 2 3 4
No termination.
Termination of both T and R in 2-wire connection.
DIP-switch settings
RS485 general advice
S5 DIP-SWITCH
>
RS485 termination
ON
1 2 3 4 5 6 7 8
S1.
ON
1 2 3 4 5 6 7 8
S2.
ON
1 2 3 4 5 6 7 8
S3.
ON
1 2 3 4 5 6 7 8
S4.
S5.
FACTORY DEFAULT
ON
1 2 3 4
= Termination
DIRI
S
A20
DIRI
S
A40
COUNTI
S
Ci
Max 0.3 metre
T+
T–
T+ T+
A
-
T
-
T
B
2-wire termination
Termination recommendations
The RS485 line must be terminated. In the modem, the
termination is combined with fail-safe functionality.
The termination is used to prevent undefined states when
the bus is in condition:
• using 2-wire RS485 both ends should be terminated.
RS485 connection pins can be differently named. For
some equipment brands the T
+
corresponds to A, but
other brands might use some other naming convention.
If a unit does not work it can help to swap A and B.
INTER 114 A GB
