Maybe. You have to ask the court for permission for the witness to testify by phone and you have to have the other party or other attorney’s permission. If there is no objection and if the court has given permission for your witness to testify by phone, then you will have to arrange for a notary public to be with your witness and swear the witness in for testimony. The notary public may also have to certify your witness’s identity.
If there is an objection or the court denies your request for a witness to appear by phone, then you would have to depose the witness for the purpose of trial testimony and you will have to hire a court reporter local to the witness.