Terrasat IBUC 3, Operation Manual

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Service and Maintenance
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7-29
Engineered to Endure
Figure 7.6
Hand-held Terminal
• Frequency Shift Keying: FSK is multiplexed onto the IF cable by means of an
FSK-modulated signal. FSK for redundancy commands operates only in ASCII
mode. For more information about commands and values available in ASCII mode
for Tx redundant systems, see Appendix F . FSK and RS485 are tied together by
the mode of operation (Legacy Binary or ASCII). Once the mode is selected, both
will work in the same mode.
For more information about FSK specifications, see
Chapter 5 .
• RS485: Two-wire half duplex which is on a separate cable. There are two modes
of operation for RS485 interface: ASCII mode and Legacy Binary mode.
Commands for redundant systems are available only in ASCII mode.
RS485 in ASCII Mode
The RS485 interface is a standard two-wire interface (DATA+, DATA-). The baud
rate is programmable to 1200, 2400, 4800, 9600, 19200, 38400, 57600 or 115200
baud. The data is transmitted asynchronously at 8 bits, no parity, 1 stop bit.
Basic protocol:
Start of Packet: < (ASCII code 60; 1 character)
Target Address: (4 characters)
Address De-limiter: / (ASCII code 47; 1 character)
Instruction code: (n characters)
Code qualifier: = (ASCII code 61 or 63; 1 character)
Optional arguments: (n characters)
End of Packet: Carriage Return (ASCII code 13; 1 character)
Example: <0001/CPE=1234{CR}
Commands and values available in ASCII mode for Tx Redundant Systems can be
found in Appendix F .