Can't receive faxes anymore

Hello mda2185 and welcome,

Please see my comments/questions below. Thanks

I can send faxes just fine and I can receive faxes when sent from my own internal extension lines - but not if it comes from the outside lines.

Please clarify what you mean by  "but not if it comes from the outside lines."?  Your FAX machine must be connected to your Comcast Telephone Numbers that are connected from the Comcast Telephone modem to your business patch panel front end, which is then connected from your patch panel back-end to your business telephone wall jacks through your internal telephone wiring. I presume that your FAX machine is connected to one of  these telephone wall jacks.

Whenever you have any FAX transmission issues, the first thing you should do is plug in a telephone into the FAX machine extension jack and see if you have dial tone into you FAX machine. If you should initialize the FAX machine as follows:

1. unplug the FAX machine telephone cord from the wall jack, then unplug the power cord for 30 seconds.

2. reconnect the telephone cord, then reconnect  power cord and wait until the FAX machine is ready.

Many times FAX machine find there wat into an infinite FAX modulation loop and this is the only means by which to correct the situation.

However, if you do not have any dial tone on the telephone connected to the FAX machine phone extension jack, make sure that the telephone cord is securely connected between the FAX machine line in jack and the wall jack. Sometimes if you wiggle the wall jack cord and the phone dial tone is restored, this point to an intermittent wiring connection at that wall jack. If you still do not have any dial tone at your FAX machine extension jack, you need to proceed as follows:

1. Contact 8003913000 option 1, have the technical agent check all you telephone switch setting to that telephone number, then reset you telephone modem. After your telephone modem rests and fully initialized, first you check to see if you have dial tone on that FAX Telephone extension. If you do then problem resolution established. If you do not, then have the technical agent call your FAX telephone number and trace this call he/she is placing to you FAX Telephone number. If it rings for him and he traces it into your telephone modem, this means you have an internal backend patch panel to that wall jack telephone wiring issue. You must then contact a certified telephone electrician to come in a trace out and fix this internal business wiring issue.

Hope this helps you out. 

I have ... or *had* ... or am *supposed to have* 3 full feature lines.

all 3 lines are (were) set to hunt to each other (round-robin; 1->2->3->1).  no one should ever get a busy signal unless all 3 lines are engaged.

all 3 lines are set to the caller ID of our published line (9797) so that we can call out of any line without having people call back in on our other lines.  when we leave for the day, we forward only 9797 so that we have lines to call in to a back-door of our phone system.  if anyone calls a line other than 9797, then they do not get forwarded as designed.

I have not had, and do not need, a dedicated fax line.

my phone system takes incoming calls and routes them to the fax machine if a fax signal is detected, regardless of the line that the call comes in on.  we give a particular number, when requested, to receive faxes but it's not published as a fax number or dedicated to faxes.  the reason we give a particular number is in case we have to change it.

this all worked for the last 2+ years.  in addition, I was able to use my credit card terminal over the phone line.

sometime after the end of July 2014, something changed and no one can figure out (or admit) what.

we stopped receiving faxes - we don't get that many so it wasn't immediately apparent.

we stopped being able to use our credit card machine over the phone line.  we had to change to IP only.  (our merchant service told us that the terminals don't ordinarily work over digital lines anyway but ours did until the weekend of 8/23 - that's when we had to change to IP)

in the process of trying to "troubleshoot" the problem, some technician:

1. changed the custom caller ID information - so now people are calling in on the wrong lines when they "reply" by caller-ID

2. changed the hunt group so now only the 3rd line does not forward to the 1st.

3. told me that the only solution is to have a "dedicated" fax line which I didn't have to have until this problem, that I did not create.

since we don't have to use the credit card machine over the phone line and there are "online fax" options available, we were considering dropping the 3rd line anyway.  so in the process of trying to force us into a 4th unnecessary line, comcast may have actually done themself out of the 3rd line that we don't really need anymore.