on the telephone

*on the telephone

 and *on the phone
Fig. speaking on the telephone. (*Typically: be ~; get ~.) She's on the phone but won't be long. Please take a seat while I'm on the phone. Get on the phone and call him back immediately!
See also: on, telephone
References in classic literature ?
Someone wishes to speak to your ladyship on the telephone," the girl announced.
She was amazed to find herself already committed by William and Cassandra to marry the owner of the halting voice she had just heard on the telephone.