This is just a FYI for those using the Trimble version of the UCCM module. I was messing around with the UCCM SCPI CLI and discovered a few hidden commands: diag:monitor, diag:version? and diag:tsip. diag:monitor makes the receiver seem unresponsive, but I expect it puts it into ROM monitor mode to perform a firmware upgrade, which on most Trimble products means that it's expecting STX/ETX wrapped commands. I haven't experimented with it much. diag:version? prints a different version number than what is shown when SYSTem:STATus? is run, maybe it's the version of the GPS core code that will be shared among other Trimble DSP receivers, rather than the version built specifically for the UCCM. diag:tsip dumps the receiver into TSIP mode, it can be controlled from within Trimble's Visual Timing Studio, or Lady Heather. If anyone has a UCCM that still boots to the CLI but is no longer functioning as a GPSDO, I'd love to buy it. Experimenting with the monitor commands could be potentially fatal, and I don't really want to sacrifice a functioning module, but I'd really like to get a dump of the firmware to explore. - Keelan