ADPRO VM22A, Issue 6
20
Channel Selection
For VM22 mode of operation, channel selection is
Protocol
achieved by application of an inverse BCD code to the
Expansion I/O port (refer to Section 8.0). For VM22A
operation, channel selection is achieved using a serial
protocol. The protocol is described in Section 9.0.
Dimensions
Unsealed beige coloured plastic case for indoor use.
205mm x 165mm x 65mm.
8.1 inches x 6.5 inches x 2.6 inches.
Weight
650 grams (23 oz).
Operating Conditions
Operating temperature range 0
o
C-50
o
C (32
o
F-122
o
F).
Humidity less than 90% non-condensing.
Warranty
Twenty four (24) months.
7.0 BCD Codes (Fast Scan Operation)
The four BCD address lines on the Expansion I/O Interface are used to select the
active channel on the VM22A when VM22 mode is selected. The following table
shows the BCD code and the corresponding channel allocation.
BCD CODE
(Bit 3 2 1 0)
MICROPHONE/LINE
INPUT NUMBER
SPEAKER
OUTPUT NUMBER
0000
None
None
0001
None
None
0010
None
None
0011
None
None
0100
Ground
None
0101
Ground
None
0110
10
10
0111
9
9
1000
8
8
1001
7
7
1010
6
6
1011
5
5
1100
4
4
1101
3
3
1110
2
2
1111
1
1
Table 3 – BCD Codes
