Though ISDN is not as fast and as cheap as the new technologies used for internet access but one can assure consistency in data flow. Then you will also experience voice clarity which is unmatched by other phone services. In ISDN the caller id is available for no additional cost. In comparison to DSL the maximum distance from the central office in ISDN is much greater. And if you are using ISDN-BRI then there is a possibility of using the low-bandwidth which is 16 Kbit per seconds. Another advantage is that when the phone call ends, the bearer channel can immediately dial up and re-connect to the data call. Then the call setup is also very quick and easy.