Elecraft KAT500 Serial Command Reference - Manual (Page 3)

Serial port overview
All commands and their responses use the printable ASCII character set. Commands are sent to the
KAT500 via its “PC DATA” serial port. Use 4800, 9600, 19200, or 38400 bit/s, 8 bit characters, one stop
bit and no parity. There is no flow control. The KAT500 Utility discovers the KAT500’s serial port speed
by sending a few null commands (semicolons) at each of the speeds and selects the speed that results in
responses. You can change the KAT500’s serial port speed with the Baud Rate (BR) command.
Beginning with firmware version 01.38, the microcontroller may be configured to be asleep when
logically “off” or otherwise idle. It takes a few serial port characters and about 100 milliseconds to wake
up, and characters sent during the wakeup period may be lost. The KAT500 Utility sends semicolons at
approximately 100 millisecond intervals until the KAT500 firmware begins to respond. See the SL
command.
Command Format
Commands sent to the KAT500 are either GET or SET.
GET commands are used to get information from the KAT500, the KAT500 provides that information in a
RESPONSE message.
SET commands are used to change the KAT500’s internal state or to initiate an action. SET commands do
not generally generate a RESPONSE. SET can be followed by a GET to verify the SET. In some cases (FT;) a
SET causes a response at the completion of an action. RESPONSEs normally look like the corresponding
SET command.
Each serial command is terminated with a semicolon character. For example, to query the current
software version, send “RV;” (send R, V, and semicolon).
Examples:
RV; GETs the firmware version number. The RESPONSE is of the form RV01.13;
AN1; SETs the KAT500 to use Antenna 1. There is no response.
AN; GETs the currently selected antenna. The RESPONSE is of the form AN1;
Generally, after sending a GET command, wait for the corresponding RESPONSE before sending more
commands. The KAT500 has a limited input command buffer. You may safely “stack up” 64 bytes of
commands without risk of overrun. If you wish to send a very long sequence of SET commands, break
them up with an intervening GET (such as the null command or RV;) that returns a RESPONSE and wait
for those responses. Flow control is done at the application level.
Using KAT500 Utility to Test Commands
The KAT500 Utility Command Tester can be used to try individual commands. Try typing “RV;” in the
input area. The command and its response are shown on the output area.