More Than One Receiver Per Line, Connection With Twisted Pair Cable (Multipoint Connection) - Videotec DTRX3 Manuel D'instructions

RS485A
RS485B
Note: Terminals RX-485A and RX-485B which have the load inserted, should be connected to terminals TX-485A and
TX-485B respectively of the preceding unit, which also have the load inserted:
NB: For the connection in question (point-to-point) faulty operation of one of the receivers will switch off all the devices
in cascade.

More than one receiver per line, connection with twisted pair cable (multipoint connection)

All receivers connected to the same line should use the same communication protocol RS485.
For each of the lines the following remarks are valid:
• only one of the keyboards (that at one end of the line) has the load inserted
• only one of the receivers (at the other end of the line) has the load inserted
• the total length of the line should not exceed 1200 m
Line A on keyboard DCS3 has been used for communication with the telemetry. The ends (Keyboard - Receiver A3)
should have the termination resistor inserted. Receivers A1, A2 should not have the termination resistor inserted. The
maximum line length, from end to end (from the keyboard to receiver A3), is 1200 metres.
NB: For the connection in question (multi-point) faulty operation of one of the receivers will not influence the other
receivers.
Keyboard phone cable
connectors
RJ11 'A' or 'B'
RJ-Jack
white -----------------------
yellow -----------------------
Pag. 12
DTRX3
RX-485A
RX-485B
MNVCDTRX301_1623_EN