Westermo MD-21 - Manual (Page 6)

RD
▼
TD
▼
TD
▼
RD
▼
Connecting the MD-21 in a 20mA current loop
12 6151-2002
3
4
3 4
RD
1 2
1
2
▼
▼
▼
▼
▼
▼
▼
3 4 1 2
▼ ▼ ▼ ▼
TD
▼
TD
▼
TD
Master
S1: 3 on
S3: 1, 2 on
S4: 3–6 on
S1: 3 on
S3: 1, 2 on
S4: 1, 2 on
Slaves
▼
RD
▼
RD
▼
3
4
3 4 1 2
1
2
▼
▼
▼
▼
▼
3 4 1 2
▼ ▼ ▼ ▼
TD
Master
S1: 3 on
S3: 3–6 on
S4: 3–6 on
S1: 3 on
S3: 1, 2 on
S4: 1, 2 on
Slaves
▼
RD
▼
Functional description
When transmitting from the master, RD and TD flash. RD flashes on both slaves.
When transmitting from a slave both RD and TD flash and on the other slaves and
the master RD flashes.
Functional description
When transmitting from a slave the TD led flashes only on that unit. The RD led flashes
only on the master modem.
When transmitting from the master, TD flash. RD flashes on both slaves.
Half duplex transmission
Full duplex transmission