Our local extensions are 3 digits long. We also have another location (not on our 3cx, but they are listed in contacts) that uses 4 digit extensions. We can dial to and from them with no problem, and they show in the call logs correctly. HOWEVER when the call comes in, the (yealink) phones and any 3CX clients display the incorrect caller ID. It seems to be truncating the number to 3 digits, and displaying THAT (local) person's name, instead of the correct one. For example, if we have a local extension 234 which belongs to John Smith, but a call comes in from the other company from Martha Jones at extension 1234... it will appear to be from John Smith at 234 instead. If the call logs can show the correct caller name and number, then I think we should be able to make it display correctly also, but I am stumped as to how.