IBUC Operation Manual 6-6
Terrasat Communications, Inc.
Rev. A
Example: <0001/CPE=1234{CR}
Commands and values available in ASCII mode are shown in the command set,
Table 6.9.
RS-485 in Legacy binary mode:
For RS-485 interfaces operating in Legacy-binary mode, the data will be transmitted at
9600 bit/s with 8 data bits, no parity, and one stop bit. In order to maintain
synchronization, the RS485 receiver will reset if a message is not completed within 50
ms of initiation.
The BUC is capable of responding to messages at rate of one every 20 ms.
For the RS-485 interface, the packet is encapsulated inside of a data link layer packet
which has an address “header” byte and a checksum “trailer” byte. The packet format is
as follows:
Byte Description
1 RS-485 Destination address of command. For responses, responder
address is shifted left by 4 bits.
2 through N Command or Response Packet with CR/LF termination.
N+1 CHECKSUM; The sum of Bytes 1-N+1 should equal zero.
Each transmitted data packet consists of 7 bytes as shown in table 7-1.
Table 6-2 BUC Data Packet Byte Configuration
The 1
st
byte contains the BUC address that is being queried. The BUC will only accept a
command if the 1
st
byte contains the appropriate address.
The 2
nd
byte contains the major command. See table 6-3 for possible commands.
The 3
rd
and 4
th
bytes contain the specific command values. See table 6-3 for possible
commands.
The 5
th
byte is used for factory settings only.
The 6
th
byte is not used.
Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
BUC Address Command Data Byte 1 Data Byte 2 Factory Use Not Used Check Sum
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