I have a FreePBX/Asterisk system I set up in 2018. It ran fine for years, now I have a problem that calls are being hung up on. I have two “CO” copper lines going into a PCI telephony card. One line is a real AT&T CO line, the other is provided by a Spectrum voice modem, via copper pair.
It seems that a lot of calls on the Spectrum line are getting dropped. The caller hears the ring, then it changes to a busy signal. I do get the caller ID shown on the stations, but when I pick up I get a dial tone. I have not changed any settings in a long time, but this behavior seems to be new. I am not sure if the AT&T line is also doing this.
Any help would be greatly appreciated!
Thanks,
Jon
I’ve not used our charter phone line for a very long time. (Paying the monthly fee for a single VOIP line is less expensive than not having it due to the discount we get for having ‘bundled services’, so there’s an extra modem in our rack that does absolutely nothing. 
) Is there any call log or error report in your customer portal?
If I were in your position, first thing I’d work on is isolating where it’s happening. If only one provider, give them a call. If both, then start looking at your PBX. The ‘full’ log should give you hangup causes; you can translate the numeric value into what caused the hangup at Hangup Cause Mappings - Asterisk Documentation