NT5K19 Analog Tie Trunk Card 3-11
UK Trunk cards description 553-3001-173
Dialing
The outgoing PBX sends address digits in the form of 10 pps pulses of
signalling tone (2280 Hz). Dual Tone Multifrequency (DTMF) transfer of
address information can also be used.
Answer
When the called party answers, the incoming PBX applies an answer signal
to the signalling path. The incoming PBX is now in the tone-off condition.
The continued receipt of the seizing signal is accepted by the incoming
PBX as a forward hold signal. The continued receipt of the answer signal
is accepted by the outgoing PBX as a backward hold signal.
Call disconnect
Either party can disconnect the call by applying the appropriate signal. The
incoming PBX applies a “clear back” signal, while the outgoing PBX
applies a “clear forward” signal. The circuit remains busy until both clear
forward and clear backward signals have been exchanged.
Table 3-7 provides a summary of NT5K19 AC15 signalling states.
Table 3-7
Summary of NT5K19 AC15 signalling states
Si gna l
Out g oi ng PB X
I ncomi ng PB X
I dl e
To ne- on
To ne- on
Sei z e
To ne- off
—
Fo rw ar d H ol d
To ne- off
—
Di al i ng
To ne- on pul s es
c orr es pondi ng to di gi t
s ig nal s ent
—
Ans wer
—
To ne- off
Bac kw ar d H ol d
—
To ne- off
Cl ea r For w ar d
To ne- on f or l onger than
300 ms
—
United Kingdom
United Kingdom
United Kingdom
United Kingdom
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United Kingdom
