It's far more likely to be a line fault
such as a poor connection at a pit in the street, at the exchange, or within the wiring of his house, or maybe even a fault with one of the devices on the line (phones, dialup/ADSL modems, faxes, monitored alarm systems.) Perhaps he should contact his telco?
(s0WmVHAwZgpG, Sun 10 Jul 2005, 6:39, archived)