Our previous What are the ISDN Layers? article briefly touched upon the concept of Point-to-Point Protocol (PPP). This technology is used to transfer data. Data transfer using PPP may occur over a digital telephony system such as Integrated Services Digital Network (ISDN) or the standard Public Switched Telephone Network (PSTN). An important distinction is, as mentioned earlier, PPP is used to transfer data, however; it is not used in ordinary voice communication over the telephone.…
Last Updated on May 15, 2026