/ CCS / Communications engineering / telecommunications / Computer networking & communications / Computer networking and communications / COMPUTERS / Networking / General / digital communication systems / Frame Relay / Header Error Control / integrated digital network applications / ISDN Access / ISDN terminal / Network architecture / Network Provider / OSI Model / Primary Rate Interface / signalling protocols / Switching Nodes / Synchronous Transport Module / TECHNOLOGY & ENGINEERING / Telecommunications / telecommunications engineering / Telex Network / Trunk Network / User Network Interface / Vice Versa / Virtual Container / Virtual Path Identifier