Its official function is to clear the comms buffer but how it actually achieves that I don't know. It's probably just a glitch since you are doing it in anger but it can work from time to time
You need to make sure the ComIP has outbound access to the receiver and your Montex receiver has inbound access on port 10001, make sure coms is started in setup on Montex
In Program Digi your Primary No. should be the receiver IP address in this format xxx.xxx.xxx.xxx/10001
I suspect the way the people who make the regs will have looked at this is, is that it is catastrophic failure (i.e. not likely to happen). Unfortunately they don't seem to realise how simple it is to block GSM/GPS signals and cut telephone lines, you can do both outside the protected area for heavens sake