Nortel DMS-100 Series Maintenance Manual page 160

4-6 Signaling for RLCM
Dial pulse signaling The LCM of the RLCM performs dial pulse digit
collection. With dial pulsing, the number of on-hook intervals in a train of
pulses represents the numeric value of the digits.
Short off-hook intervals separate the on-hook intervals of the digits. Long
off-hook intervals separate the digits. The break time expressed as a percent
of the pulse period (break + make duration) is the percent break.
The three important characteristics of dial pulsing are speed, percent break
and interdigital time. The host XPM analyzes these characteristics and
assigns a channel or time slot in the digital line.
DTMF signaling Digitone phones send dial pulse or dual-tone
multifrequency signals to transmit address information over a line. During
normal operation, the remote maintenance module (RMM) forwards this
signal to the host. The ESA operation sends this information to a Digitone
receiver in an RMM.
The DTMF signals are specified groups of tones that represent digits (0-9)
and many other special units. Special trunk interface circuits decode the
tones to digits. The DT and MF receivers are special trunk interface circuits.
The RMM of the RLCM examines the output of these receivers to determine
when a digit is received. The RMM relays the digits from the MF receiver
to the host XPM. The host XPM analyzes the digits and applies a ringing
signal to the called line.
End-to-end signaling
End-to-end signaling allows a subscriber to send DTMF signals to the far
end. The subscriber uses the keypad of a Meridian Digital Centrex (MDC)
Meridian business set (MBS) to send these signals. The subscriber can
outpulse DTMF signals to the machine that start, stop, rewind and playback
the recordings on tape at the machine. The subscriber presses fixed keys at
the MBS. After each 130 ms DTMF signal, the PCM signal reconnects.
297–8351–550 Standard 04.01 August 1999