FreePBX running on top of VirtualBox.
I am using 2nd hand Planet VIP-480 for ext FXO and FXS. The reason I am using it because that the cheapest I found.
It has some bugs like:
-LAN pc can’t resolve name but can ping dns
-sometime the text I input for some settings will be disappear when I logout
Its old device, can’t complain for that
For FWT (Fixed Wireless Terminal), it can call to 4 different GSM provider.
I don’t know yet whether it can concurrently call 4 GSM or one at a time.
But for incoming call, only one can be set. You can choose which SIM will be active.
Its smart enough to select outgoing call to which SIM card or PSTN
Its good for Customer Service or Marketing department
Still need to figure out Incoming Call setting. Outgoing call so far ok.
Need to retest