12.5 Switching Malfunctions
Problem Remedy
The switcher succeeds
in switching a number
of sources then fails to
switch one.
Malfunction in the particular source or cable assembly.
NOTE
The most common failure mode in transferring the signal of
an audio source is a break in the connecting wire.
Disconnect the source from a channel that is switching successfully and connect the
suspect source to it. If the channel continues to switch successfully, then there is
something wrong with the Matrix Switcher or the suspect source was not connected
properly. If it does not continue to switch successfully, then there is something wrong
with the source or cable assembly. Check them.
The Matrix Switcher
turns ON but will not
switch at all
One of the two flat cables leading from the main board to the control board may be
disconnected and the switch command is not being transferred to the Matrix
Switcher. Check them.
13 COMMUNICATION PROTOCOL
Communication with the Matrix Switchers described in this manual uses four bytes of information as defined
below. Data is transferred at 9600 baud with no parity, 8 data bits and 1 stop bit.
1st byte
DESTINATION INSTRUCTION
0 D N5 N4 N3 N2 N1 N0
7 6 5 4 3 2 1 0
MSB LSB
2nd byte
INPUT
1 0 0 0 I3
7 6 5 4 3
3rd byte
OUTPUT
1 0 0 0 O3
7 6 5 4 3
4th byte
MACHINE NUMBER
1 0 0 0 0 M2 M1
7 6 5 4 3 2 1
1st BYTE: Bit 7 – Defined as "0", D – “DESTINATION BIT”
This bit is always "low", when sending from the PC to the Matrix Switchers, and "high" for information sent to
the PC.
N5…N0 – “INSTRUCTION”.
The function that is to be performed by the Matrix Switcher (s) is defined by these 6 bits. Similarly, if a function
is performed via the machine’s keyboard, then these bits are set with the INSTRUCTION NO. which was
performed. The instruction codes are defined according to the table below (INSTRUCTION NO. is the value to
be set for N5…N0).
2nd BYTE: Bit 7 – Defined as "1".
Bits 4 – 6 - Defined as "0".
I3… I0 – “INPUT”.
When switching via RS-232 for RS- 485 (for instruction codes 1 and 2), these bits set the input that is to be
switched. Similarly, if switching is done via the machine’s keyboard, then these bits are set with the input