The phrase "a telephone which" is correct and usable in written English.
You can use it when providing additional information or describing a specific type of telephone.
Example: "I bought a new telephone which has advanced features like voice recognition and touch screen."
Alternatives: "a phone that" or "a device which".
He has access to a telephone, which he used for an interview this week.
We had a guy who was living in a house without a telephone, which is not very common, and we had a time before the Internet, the third factor.
And for pure comedy nothing beats their cantankerous pas de deux over the answering of a telephone, which they approach as if it were an exotic beast with a volatile temper.
UNDOING When his no-good therapist puts him into a trance, Rivers is unexpectedly roused from his slumber by another irritating bell — a telephone — which sends him into a frenzy and causes him to murder the evil doctor.
Her only links to the outside world are an old computer, which she uses mostly to pay bills and keep up with current affairs, and a telephone, which she uses mostly to chat with her psychiatrist.
The newspaper started life in a tiny office, equipped with one desktop computer, an old printer and a telephone, which served as their base right up until the ban on independent media, according to fellow exiled journalist Yebio Ghebremedhin.
During the standoff, the police gave the man a mobile telephone, which he used for an interview with a radio station.
You'll need a landline telephone, which works better for phone interviews than a cell phone, and voicemail or an answering machine, and possibly a fax machine.
His family borrowed several hundred more yuan soon after his arrival in Britain to buy him a mobile telephone, which they mailed off to England.
They handed Mr Smulian $5,000 for expenses and told him that they wanted millions of dollars' worth of weapons.They gave him a mobile telephone which they claimed could not be monitored (it was, naturally).
The first uses a normal analog telephone, which is attached to a special converter that sends calls over the Internet.
