Caller Hangs up, no Record in Log, at least once a day

[Homercidal]

We get these calls nearly every day, sometimes 2-3 times a day, usually several calls in a row.  Nobody answers when we pick up.  It is silent for several seconds, then the call disconnects.  It's VERY frustrating, mostly because it rings through our Shop PA. 

I've downloaded the logs immediately after the call, but I don't see the call coming in.  I can see my attempt to pick up the line from my desk, but there isn't a log entry that I can see to find out what kind of call it it, where it's coming from, etc.

I'd love to make this stuff stop, but I'm mostly interesting in making sure there isn't a problem with connecting to a specific number.  I don't want to miss important calls from customers, etc.

I'm adding the call log in case it is helpful (I have X'd out some numbers for privacy.):

 12/21 08:56:31  0000:00:29 584          511 1231349xxxx           AFT7         
                            171   171511                                  A171023
 9 A A1711519                                                                   
  12/21 08:56:31  0000:00:00 511          511 1231349xxxx           AFT7         
       584                  171   171511                                  A171151
 9 A                                                                             
  12/21 08:53:59  0000:00:36 T1      **** 231832xxxx 514              514       
                            171   2318322750           231832xxxx         A171151
 8 A                                                                             
  12/21 08:54:12  0000:00:05 T1003   0003 *599                      T 513       
                            171   T1711003                                A171024
 4 A                                                                             
  12/21 08:54:04  0000:00:05 T1003   0019 *599                      T 513       
                            171   T1711003                                A171023
 3 A                                                                             
                                                 
 LOGSYS info: READ completed for SMDR log with 20 entries.                       
 

[ralph]

What does it say on your display when the call is ringing in?

You may also want to enable internal SMDR just to be sure it's not an internal device calling.

Ralph

[Homercidal]

It shows ANALOG CALL or something like that.  I'm wondering if it's a fax machine or a Fire Alarm system checking the circuit.  We used to have our fire alarm system use analog ports to call their HQ, but we changed to using Cellular because it was cheaper and potentially more reliable in case of power outage or fire.

I would have expected to see something in the call log, in any case.  I'll be honest, I'm not much of an expert on phone systems.

There may be a way to check all of the analog ports and see which one is on a fax machine and check routing to see if it's set to forward on no answer.  Heck, I don't know.

[ralph]

Look in your Trunk Attributes form to see if you have a label that says "Analog Call."
I'm betting it's an external call ringing an unused analog trunk.  It may be difficult to narrow down the source without caller ID.

Ralph

[Homercidal]

The phone displays "Analog Trunk".