It is the 124 I. I didn't catch what software level it was. The customer had me move the extensions around but not work on this. From what I gathered talking to her is....It will work a time or two then not work several times then start working again. But, on the times it doesn't work she is getting a message saying you need to dial a one. I am thinking that the system is doing its job. She is having problems with her telco.