Comtech EF Data LBC-4000 - Manual (Page 75)

LBC-4000 L-Band Up/Down Converter System Revision 4
Serial-based Remote Product Management MN/LBC4000.IOM
6–3
6.2 Remote Commands and Queries Overview
6.2.1 Basic Protocol
Whether in EIA‐485 or EIA‐232 mode, all data is transmitted as asynchronous serial characters, suitable for transmission and reception
by a UART. The default asynchronous character format is 8‐N‐1 (8 data bits, no parity, one stop bit).
The supported baud rates are 1200, 2400, 4800, 9600, 19K2 (19200), or 38K4 (38400) bps.
All data is transmitted in framed packets as asynchronous serial characters, suitable for transmission and reception to the Controller using a
universal asynchronous receiver/transmitter (UART). 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:
• Controller‐to‐Target – The Controller device (e.g., the user PC) is used to transmit instructions (commands) to – or to request
information from (queries) – the Target device (i.e., the LBC‐4000).
• Target‐to‐Controller – The Target, in return, only transmits response information to the Controller when specifically directed by
the Controller.
For Serial Remote Control, all issued commands (Controller‐to‐Target) require a response (Target‐to‐Controller). This response is either
to return data that has been queried by the Controller, or to confirm the Target’s receipt of a command to change the Target’s
configuration.
6.2.2 Packet Structure
The exchange of information is transmitted, Controller‐to‐Target and Target‐to‐Controller, in packets. Each packet contains a finite
number of bytes consisting of printable ASCII characters, excluding ASCII code 127 (DELETE).
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.