EHS6T stops responding | Telit Cinterion IoT Developer Community

I am attempting to drive the EHS6T via HyperTerminal.

On power-up I get the message:

^ SYSLOADING

^SYSSTART

I can issue AT commands initially, ie AT+COPS?

These are echoed back from the EHS6T and viewable on HyperTerminal (local Echo is OFF).

And I get the expected reply, with OK from the EHS6T.

The above suggests basic communications are OK.

However after about 5 secs The EHS6T stops responding – no characters are echoed back to HyperTerminal in response to inputted commands.

If I power down / up the above process can be repeated.

Any clues to keep the EHS6T operational ??