A basic introduction to digital trunks

1. Basic Rate

2. ITU Reference Model for ISDN PTT Equipment at Phone Company Switch U Interface Termination Point T Interface Termination Point S Interface Termination Point Standard PSTN Equipment has an R Interface Termination Point U T S R TE2 TA TE1 TE1 NT1 NT2 ISDN Equipment that can connect directly to an ISDN Line Terminal Adapter used to connect TE2 devices to an ISDN line Equipment that cannot connect to an ISDN line Network Termination used to convert U into T interface Network Termination used to convert T into S interface

3. Function Groups & Reference Points LT NT 1 NT 2 TE 1 TE 2 TA

4. Function Groups & Reference Points LT NT 1 NT 2 TE 1 TE 2 TA U T S R

7. NTE 8 The NTE8 (opposite) is the normal NTE within the customers premises for an ISDN2e connection. The NTE8 has TWO RJ45 sockets - ONLY ONE IS TO BE USED - the other is for testing purposes

14. S0 Bus RJ 45 Outlet Terminating RJ 45 Outlet RJ 45 Outlet RJ 45 Outlet RJ 45 Outlet RJ 45 Outlet RJ 45 Outlet RJ 45 Outlet

17. PRIMARY RATE

19. NTE Status Lights BT Testing ON or Flashing Test Amber OK OFF Test Amber Network Faulty ON BT Red Network OK OFF BT Red Two or more inputs disconnected Flashing Customer Amber One input disconnected ON Customer Amber Inputs OK OFF Customer Amber NTE on Standby Battery Flashing Power Green No power to NTE OFF Power Green NTE on mains power ON Power Green Indication Status Light

20. Primary Rate Interface The PRI is supplied through a standard 2.048Mb/s E1 channel. This comprises of 30 64Kb/s B channels and one 64Kb/s D channel

22. DASS II Is presented Like This

23. ISDN 30

24. E1 Is Presented Like this

25. The Connection + Power Source/ Sink 2 8 - Power Source/ Sink 2 7 - Transmit/ Receive 6 - Receive Transmit 5 + Receive/ Transmit 4 + Transmit/ Receive 3 - Power Source/ Sink 3 2 + Power Source/ Sink 3 1 Polarity Signal Pin