5
X
RS-232,485 + 2
X
E
THERNET
/2 M
BIT
/
S
G.703 (G.704) M
ULTIPLEXER
O
PERATING
M
ANUAL
IOA81-1E
9
August 2004
Attaching the terminating resistor simultaneously induces line bias as shown below.
Fig. 11.
TM-81.1 multiplexer - connecting of terminating resistor and biasing the line.
Each port of the TM-81.1 multiplexer, once configured for RS-485, can work in two
modes of transmission, i.e. half-duplex or duplex mode. Setting the operating mode up is
possible by using a set of configuration switches located on the front panel of the device.
When the device is to work in half-duplex mode and transmit through one twisted
pair, it is necessary to short the circuits RD+
→
TD+ and RD-
→
TD- on the cable at-
tached to the multiplexer.
RD+
RD-
Ground
Vcc