Comtech EF Data LPOD - Basic Protocol; Eia-232; Packet Structure

LPOD Outdoor Amplifier / Block Up Converter (BUC) Revision 9
Serial-based Remote Product Management MN-LPOD
5–6
5.1.2 EIA-232
This is a much simpler configuration in which the Controller device is connected directly to the Target via a two-wire-plus-ground
connection. Controller-to-Target data is carried, via EIA-232 electrical levels, on one conductor, and Target-to-Controller data is carried
in the other direction on the other conductor.
5.1.3 Basic Protocol
Whether in EIA-232 or EIA-485 mode, all data is transmitted as asynchronous serial characters, suitable for transmission and reception
by a UART. The character format should be 8N1 (8 data bits, no parity, 1 stop bit). The baud rate may vary from 2400 to 38400 baud.
All data is transmitted in framed packets. The Controller is assumed to be a PC or ASCII dumb terminal, which is in charge of the process
of monitor and control. The Controller is the only device that is permitted to initiate, at will, the transmission of data. Targets are only
permitted to transmit when they have been specifically instructed to do so by the Controller.
All bytes within a packet are printable ASCII characters, less than ASCII code 127. In this context, the Carriage Return and Line Feed
characters are considered printable.
All messages from Controller-to-Target require a response – with one exception. This will be either to return data that has been requested by
the Controller, or to acknowledge reception of an instruction to change the configuration of the Target. The exception to this is when the
Controller broadcasts a message (such as Set time/date) using Address 0, when the Target is set to EIA-485 mode.
5.1.4 Packet Structure
Controller-to-Target
Start of Packet Target Address Address Delimiter Instruction Code Code Qualifier
Optional
Arguments
End of Packet
<
ASCII code 60
(1 character)
0-9
ASCII codes 48-57
(4 characters)
/
ASCII code 47
(1 character)
A-Z, a-z
ASCII codes 65-90,
97-122
(3 characters)
= or ?
ASCII codes
61 or 63
(1 character)
(n characters)
Carriage Return
ASCII code 13
(1 character)
Example: <0412/MUT=1{CR}