Nortel Meridian 1 Manual page 44

Page 42 of 44 Flexible analog line circuit card
Supplement to 553-3011-210
Ringers
Ringing is supplied to the telephones at a frequency of 25 Hz with a voltage
of 80 Vrms. The peak voltage is no higher than 125V.
The Flexible Analog Line Card supports any number of ringers up to a
maximum ac impedance presented to the line of 350 ohms. Table 30 shows
the number of ringers supported for various loop lengths.
Table 30
Ringers supported on each unit of the NT5K02LB card
Number of Ringers
Loop Length (Ω)
Message waiting indicator
The message waiting indicator consists of a lamp flashing at a rate of 1 Hz at
the telephone set. (A continuously lit lamp as a message indicator is not
provided). The lamp is activated by the application of high voltage
(-100V) to the ring lead.
Hookflash special features
Pressing the hookflash for a specified length of time is seen by the
NT5K02LB card as a request for special services. To access special features,
the hookflash must be pressed for at least 140 milliseconds, but no longer than
850 milliseconds.
Digipulse dialling
The NT5K02LB Analog line card recognizes loop disconnect signals with the
following limits:
Break pulse:50 to 76 ms
Make pulse:28 to 46 ms
A make pulse for longer than 350 ms is seen as an interdigit pause. Make and
break pulses of 5 ms or less are rejected.
Provisional 1.3
1 2
1000 1000
July 1993
3 4
850 600
5
350