Answer to 1 …4
1. Line signalling: represent the status of the line (hook on or hook off). Register signaling: represent the translation and storage of digits, for example digits dialled as tones from telephone are translate by a switch into digits to know where to route the call)
2. N ISDN:narrow band ISDN, it is to have over 1 single line two channel that allow to have at the same time two different calls. B ISDN: Broad Band ISDN, to increase bandwith over telephony to support multimedia
3. In band signalling that uses de same path and media to tranfer information, example R1, R2 for trunks. Outof band that siganling is over other media, example CC7 or SS7 for trunks.
4. E1 is 30 voice channel (Europe Standard), T1 is 24 Channesl (USA standard).
5. 6 apologize (not idea)