TELEPHONE lines went down in Okehampton on Monday afternoon as an exchange fault interrupted the service. Jason Mann, BT spokesman, said around 4,900 customers were affected by the fault which lasted for approximately one hour and a quarter. He said telephones in the town centre and in some surrounding areas could not dial out or receive calls while the fault was corrected. The problem occurred at around 4.15pm following a fault at the Okehampton exchange and was resolved just after 5.30pm, when replacement computer equipment was installed. Mr Mann said many customers may not have even been aware of the problem, but he apologised for any inconvenience.