Nortel Networks Video Gaming Accessories 553-3001-211 Manual De Usuario

 NT1R20 Off-Premise Station Analog Line card

For outgoing calls from a telephone, a line unit is seized when the telephone 
goes off-hook, placing a low-resistance loop across the tip and ring leads 
towards the NT1R20 OPS analog line card (see Table 68 on 

the card detects the low-resistance loop, it prepares to receive digits. When 
the system is ready to receive digits, it returns a dial tone. Outward address 
signaling is then applied from the telephone in the form of loop (interrupting) 
dial pulses or DTMF tones.

Far end station 
hangs up first

High resistance loop

If the far-end hangs-up first, the system 
detects disconnect signalling from the 
trunk. The person at the near-end 
recognizes the end of the call and 
hangs-up.

Line card unit idle

Ground on tip/battery on ring
High resistance loop

Line card unit is ready for the next call.

Line card unit idle

Group on tip, battery on ring
High resistance loop

No battery current drawn.

Call request

Low resistance loop

Near-end station goes off-hook. Battery 
current is drawn, causing detection of 
off-hook state. 

Dial Tone

Dial tone is applied to the near end 
station from the system.