Videotec DCJ, Operating Instructions Manual

Page: 143 / 256

Page 13
MNVADCJ01_1729
_EN
3.4 One control keyboard per line
Connection is performed by means of one standard connection cable, which is described in the previous
paragraph.
3.5 More than two devices on the same line
The presence of more than one keyboard on the same communication line requires the use of Rjjack boxes, to
be connected in the correct way. As specified in
§ 3.2 RS485 and system types, page 11
, identify the two
devices which represent the line ends and correctly terminate them (to terminate the DCJ keyboard, see
§ 2.5 -
Dip switch, page 10
).
Particular attention must be paid for the length of the stubs.
Transmitters (keyboards) Receivers
(video matrixes, telemetry)
White
RS485A
Blue
Yellow
RS485B
Black
3.6 Control of grounded devices
When using devices provided with a grounded power supply some communication problems could occur. It is,
then, required a 3-poles twisted pair cable according the following connection:
Transmitting devices
(keyboards)
Receiving devices
(video matrix, dvr, mux and telem. receivers)
White
RS485A
RS485A
Yellow
RS485B
RS485B
Red
GND
GND
RS485A (+)
RS485B (-)
GND