Videotec DCBD, Руководство по эксплуатации

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Page 11 MNVCDCBD_0351
6.4.2 More than one keyboard and receiver per line (multi-point connection)
This type of connection allows one or more keyboards (even different types from DCTEL: DCJ for example) to
control one or more receivers arranged in the same line (multi-point connection).
All receivers connected to the same line should use the same, RS485, communication protocol.
For each line, the following observations are valid:
•
only one of the keyboards (the one at an 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 1200m.
•
each keyboard should have a different address from the others
•
each receiver should have a different address from the others (between 1 and 16)
The ends (Keyboard K1- Receiver R3) should have the termination resistance inserted. Receivers R1, R2 and
the keyboard K2 should not have the termination resistance inserted. The maximum length of the line, from end
to end (from keyboard K1 to receiver R3), is 1200 metres.
N.B.: For the connection in question (multi-point), a failure of one of the devices will not affect the other
receivers.