Keep getting a busy signal when you dial a Corvallis phone number? It's not the person on the other end of the line - it's the line itself.

An undetermined number of Corvallis residents were unable to use their landline phones Wednesday night and Thursday to reach customers of other phone companies. For example, callers with Qwest phone service trying to call someone who is a Comcast customer often heard only busy signals.

Cell phone traffic was unaffected.

But questions that various phone company officials deflected on Thursday included what caused the problem, which phone services are affected and how, who is responsible for fixing it, how far it extends over what area and how long it will take to fix.

A Qwest customer service representative said the problem was with AT&T and Comcast.

A Comcast customer service agent said the problem was with all three companies, but had originated between AT&T and Qwest.

Irene Dumas, office manager at Riverside Window and Door, 439 S.W. Second St., which is served by Comcast, said the business started getting customer complaints about the phones on Wednesday.

"We started receiving angry e-mails from customers saying 'I've been trying to contact you, and the phones are constantly busy,' " Dumas said.

She called Comcast, which said the communications breakdown was due to a problem that happened while Qwest was working on a trunk line. She was told that Qwest customers can't get through to Comcast customers, but Comcast customers are not having problems calling out.

Corvallis resident John Ender had the same problem. His two calls to Comcast led to little information - except that it was a Qwest problem.

As of Thursday evening, spokespersons for Qwest and Comcast could provide no estimates for when the service would be repaired.