Videotec SM328B - Manual (Page 10)

2.1.3.2 Switching off
Turn the front switcher on OFF (O) position.
2.2 Connectors and cables
2.2.1 Video cables
Use a RG 59 coaxial cable or equivalent. Over large distances we advise using a video transmission
system via twisted pair.
2.2.2 Keyboard lines
The matrix has four RS485 lines for the keyboards connection. Each line has the RS485 load permanently
inserted, so that it must represent one of the ends of the RS485 line.
The telephone cable supplied is 1.5 m long. To connect keyboards and Videotec telemetry receivers over
greater distances (up to 1200m) us RJjack shunt boxes and a non-shielded twisted pair with minimum
diameter 0.6 mm (sect.0.22 mm² AWG 24).
The extension cables used to connect keyboards and receivers to the matrix are different!
Keyboard TX RJjack1 RJjack2 Matrix RX
RS485A white blue RS485A
RS485B yellow black RS485B
2.2.3 Aux lines
The two auxiliary lines (Aux A and Aux B) can be used to control a certain number of devices via the matrix
only if the matrix uses the MACRO protocol.
Each connecting cable described below is specific for the device being controlled. Using incorrect cables
may damage the system.
The keyboards should be properly set up to control the telemetry receiver/dome/video multiplexer.
2.2.3.1 RS485 load on the Aux lines
For the jumper settings, see the procedure described in section 2.3.2 RS485 load Jumpers on the Aux
lines, page 12.
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