Auto dial

I used to have an entry that called my home number when a burglar alarm was tripped.  Long removed that from my system.
 
Now, twice in the last month the line the ELK is attached to has called my home number for no apparent reason.  Looked at logs, no corresponding entry.  No entries at all that call any number.
 
Any ideas what may cause this?
 
Thanks,
John

Jon
 
Are you sure that it is the Elk that made the calls? I have had calls on my home phone that appear to be from the same home phone line on caller ID. In other words the line is calling itself and answering itself which is impossible. What do you hear on the line when you receive the call? I believe that there are phone dialers out there that can spoof the number that appears on the caller ID.
 
http://www.fcc.gov/guides/caller-id-and-spoofing
 
Mike.

Someone in one of the forums posted about this recently (sorry, can't remember where). Apparently easy for scammers to do this replicating of one's home number (or any number). Probably good you weren't there to answer, as you would have just had an annoyance.

Without speaking to the theory of the OP's original call, as someone who knows a ton about phone systems, spoofing Caller ID is unbelievably simple.  With a traditional PBX on any sort of PRI interface (channelized voice as opposed to POTS), the outbound CallerID is actually controlled by the PBX and not the Telco - we can put whatever we want in the outbound.
 
If you're running SIP trunks, depending on your provider, it can get even easier.   I run a very simple SIP trunk in the house and I can put whatever I want into the outbound CID. 
 
 
More semi-interesting info - only CID Number is transmitted - then somewhere at the near end of your service your provider does a CID Name Lookup against a database (there are several options) to get the Name - so when you change your outbound CID number the receiving end will pick up whatever Name is in the database queried by your provider.