Is there a "Previous" command in the protocol? I'm using RTI's two way driver, and this command isn't in the driver.

Side note: I'm having a problem with the SCH2P in that every 10 minutes or so, I lose channel up and channel down control. However, direct channel access still works, and once I select a channel, up and down work again. I want to solve this problem by jumping to a specific channel and then back to the previous one, but there isn't a command to go back to the previous channel. Unless there is.