The phrase "a public phone" is correct and usable in written English.
It can be used to refer to a telephone that is available for use by the general public, often found in public places.
Example: "I need to find a public phone to call my friend since my cell phone is dead."
Alternatives: "a payphone" or "a telephone booth".
He found a public phone and called the Peace Corps medical officer in Chengdu.
It's a contraption rather like a public phone box, with two of the walls removed.
As Maev Kennedy relates, this could often be from a public phone box.
Some L.I.R.R. riders can make calls on some trains using a public phone.
Use of a public phone costs about 50 cents, for many almost an entire day's pay.
Whenever she passed a public phone, she'd stick her fingers into the coin return, fishing around for change.
Serrano's works are set to go on display at various locations around Washington Square in Manhattan this month, transforming a subway station (at West 4th Street), La Guardia Place, Judson Memorial Church, and a few public phone booths into makeshift galleries of contemporary art.
From an untraceable public phone you call the contacts you have been given and arrange to meet somewhere neutral.
Shopkeepers cash in their accumulated phone credits with people who make money by offering callers use of their mobile phones as a sort of public phone.
But $3m in ring earnings, an addict's craving for more and an aversion to paying for anything – he even used wires to avoid putting a dime in public phone boxes – ensured that was unlikely to happen.
The police even knew that he was composing songs about killing "Western infidels," and one officer reported that Mr. Merah had stayed close to home and was acting suspiciously, with no Internet service at home, no fixed cellphone and a penchant for public phone booths.
