Sorry for delay. It's normal if there is no sim card insert. If you have pluged the sim card, that maybe the sim card was not pluged well. Please unplug the sim card and plug it again. If it still cannot work well, you can contact me via skype, I'll help you to check it.
SIM is inserted and calls work fine following a hard reset, but Elastix starts returning the 'GSM reset power of module on D-channel of span 1(Send AT Command timeout and resend failed)' after a day or two.
I've just re-installed Elastix (this time without loading the modules indicated in the install guide, as it doesn't appear to need them in this version of Elastix) and will see how it goes over the next few days. Will return to give an update then