As of 2015 North America has not accomplished full upgrade to the ISDN, and the predominant telephone service is still the older Plain Old Telephone Service.
2015'te Kuzey Amerika ISDN e ful olarak taşınmasını bitiremedi ve baskın telefon hizmetlerini, Plain Old Telephone Service(Düz Eski telefon Servisi) ni kullanmaya devam etti.