The RCH3000 is a digital remote. Meaning all functions are sent via as serial commands via the SB9600 (RS232) protocol. This function is how you change channels, see programmed channel aliases, see ID's, send call alerts...basically every interface to the consolette minus TX and RX audio. Essentially, nothing but a remote control head in a desktop remote factor. I remember the predecessor to this particular remote being setup as a W9 control head in the radio's codeplug but that was also interfaced to an Astro Spectra consolette and not an XTL consolette.
When it comes to tone remote function...different protocol. Uses a 50 ms burst of 2175 Hz called a High Level Guard Tone followed by 150 ms of what is called a function tone. This function tone can represent channel numbers, PTT, monitor, scan, etc. This is all followed by a continuous 2175 Hz burst 20-30 dB below the HLGT called the Low Level Guard Tone. The LLGT is present as long as the function is being active. PTT is commonly 1950 Hz...so there would be a 50 ms burst at 2175 Hz, 150 ms burst at 1950 Hz and then another 2175 Hz burst 20 dB below until PTT is released. The consolette or TRA would simply notch out 2175 and pass the other audio on as audio to be transmitted.