what code is 01379
01379 646504. 01379 646504 is a valid telephone number in the 01379 dialling code. 01379 is a Geographic dialling code for Diss. According to our most recent records, this number is currently allocated to BT and routed to the Diss telephone exchange.1  01379 dialling code. 2  Diss telephone exchange.1379 646504 is a valid telephone number in the 01379 dialling code. 01379 is a Geographic dialling code for Diss. According to our most recent records, this number is currently allocated to BT and routed to the Diss telephone exchange. 1  01379 dialling code. 2  Diss telephone exchange.