Elecraft KAT500 Serial Command Reference - Manual (Page 14)

PSI (Power Status Initial, GET/SET)
GET format: PSI;
SET/RESPONSE format: PSI0; or PSI1;
Determines whether the KAT500 starts OFF (PSI0;) or ON (PSI1;) when DC power is initially applied.
The KAT500’s microcontroller operates whenever DC power is applied. See the SL command.
PSI; was added in firmware version 01.37. This command is used by the KAT500 Utility Edit
Configuration dialog Initial Power tab.
RSTx (Reset, SET only)
SET format: RST0; or RST1;
RST0; resets the microcontroller without saving state in EEPROM. This is equivalent to removing the
power plug and plugging it back in again. RST1; simulates pressing the power off button which saves
current state in EEPROM before reset.
RST may be ignored while transmitting.
RV (Firmware version, GET only)
GET format: RV;
RESPONSE format: RVnn.nn;
SIDE (Select Side, GET and SET)
GET format: SIDE;
SET/RESPONSE format: SIDET; or SIDEA;.
Gets or sets the state of SIDE relay K9.
The selected capacitors are connected to the transmitter side of the inductor (a CL network) when K9 is
not energized (SIDET;)
The selected capacitors are connected to the antenna side of the inductor (an LC network) when K9 is
energized (SIDEA;).
Generally, the capacitors shunt the higher impedance side.
It may take a few tens of milliseconds after issuing SIDEx; before the relay is changed.
SET may be ignored if the current transmit power exceeds the AKIP power threshold.
The SIDE relay is released while the bypass relay is bypassed.