Jane has a Panasonic cordless phone, and when she switches from her headset to the speaker, she gets has a "chirping" noise that drives her nuts. Leo thinks that Jane is suffering from "slippage," when the cordless phone gets out of sync. It's not unusual. Jane needs a DECT headset, which is a digitally enhanced cordless phone. Leo also says that if it's from the speaker, it could be echo cancellation kicking in, which causes the chirp. That's why he doesn't like talking on speaker phone.