AVM AVM RS232, Manual

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M-series RS232 Programmer’s Manual
M-series RS232 Programmer’s Manual
7.7.3 Set Current Value
The Set Current Value message allows direct control over the attenuation at a single crosspoint. Set
Current Value cannot be used to set audio levels of a crosspoint that has been defined as part of an
A/V group (for grouped audio use the class 12 Route Video message).
To use this message as a control test, select a crosspoint to be set and encode it in the input output pair.
The example below sets the current value of the crosspoint at input 2 and output 5. The value to which the
current value is set is encoded in the current value parameter. This value can be any value from 0 (full off) to
255 (full on). The example below sets the crosspoint to 255. Since 255 is hex FF the value is escaped into
two bytes F0h, 0Fh. Sending this message consists of transmitting the following ten bytes: FAh, 00h, 05h,
02h, 0Dh, 02h, 05h, F0h, 0Fh, and 15h.
When this message is properly received by the matrix, the current value will be immediately affected, since
this command bypasses ramp time and slew rate. You should immediately hear the change in the level of the
crosspoint. Be sure that your audio source, amplifiers and speakers are all powered and working.
00h 05h
02h 0Dh
F0h, 0Fh
current value (escaped)
15h
input
output
02h
05h
7.7.4 Communication Recommendation
Because the Intelix RS232 is a “simplex” or “half duplex” bus protocol there are certain restrictions placed
on bus traffic. Any message sent from the controller to the matrix that generates a reply other than <AC-
KNOWLEDGE> must not be followed by another message until the reply is complete. To be safe, insert a
delay of 100 milliseconds after any message that generates a reply.