Comtech EF Data SNM-1010L - Manual (Page 262)

SNM-1010L Data/Control Modem Revision 0
Specifications MN/SNM1010L.OM
B.9 Transmission Interface
Each transmitted data packet consists of 7 bytes of information. The BUC only accepts a
command if the first data byte contains the appropriate address. Commands are only
executed if the checksum coincides, but a status response is sent if the address is correct
and the command number is within the valid range.
B.10 Indoor Unit to Outdoor Unit Message Structure
B.10.1 Command Message Structure (IDU to ODU)
Byte Name Description Value
1 Address Address of BUC 0x01 to 0x0f
2 Command Request Status
TX On/Off
Change Address
Set Carrier Frequency
0x01
0x02
0x03
0x04
3 Data Byte 1 Not used if command: =
0x01
TX control if command:
=
0x02
New address if command:
=
0x03
Carrier Frequency if command: =
0x04
0xAA
0=Off, 1=On
0x01 to 0x0f
MSbyte
4 Data Byte 2 Not used if command: =
0x01
Not used if command:
=
0x02
Not used if command:
=
0x03
Carrier Frequency if command: =
0x04
0XAA
0xAA
0xAA
LSbyte
5 Data Byte 3 Not Used 0xAA
6 Data Byte 4 Not Used 0xAA
7 Checksum Algebraic sum of bytes 1 - 6
B–20