Connection With The Rs485 Line; Connecting More Than One Receiver In Cascade (Point-To-Point Connection) - Videotec DTRX3 Manuel D'instructions

Connection with the RS485 line

The keyboards DCS3, DCJ, DCT and DCTEL and the receiver DTRX3 can be directly connected using the telephone
cable supplied by the manufacturer, using the RJ11 connector (J1 in the figure pag.7) present in the circuit and
referring to the table given below.
Connection keyboard – receiver DTRX3
Communication mode RS485: max. distance 1200
metres
Keyboard (RJ11 A or B)
TX-485A White
TX-485B Yellow
Note: The receiver DTRX3 has the load inserted in reception and is connected to line A or B on the keyboard with the
load inserted.
On the receiver side it is also possible to make a simpler connection to terminals RX-485A and RX-485B as in the
following scheme.

Connecting more than one receiver in cascade (point-to-point connection)

The receivers DTRX3 are able to regenerate the received signal internally and retransmit it along a new
communication line to the subsequent receiver. Each of the three sections of line (L1, L2, L3) is considered
independent, and connects only two devices point-to-point, each with inserted load, over a maximum distance of 1200
metres. The distance between the keyboard and receiver D can therefore be up to 3600 m (1200 m between keyboard
and receiver B, 1200 m between receiver B and receiver C, and a further 1200 m between receiver C and receiver D,
for a total of 3600 m).
DTRX3
------- Blue RX-485A
------- Black RX-485B
Pag. 11 MNVCDTRX301_1623_EN