Mitel SX-200 Documentation page 474

configurations, depending upon whether the trunk is a CO or Tie and
whether or not tone-to-pulse conversion is required:
If Figure 8-3(a) configuration is applicable, the dial pulses from
the extension are repeated by a relay in the trunk card and
enter the trunk circuit. The call proceeds under control of these
pulses.
If Figure 8-3(b) conditions are applicable, then DTMF tones from
the extension are routed over the speech path, through the
trunk card to the main exchange and again the call proceeds
normally.
When DTMF extension dialing is used to a DP exchange, Figure
8-3(c) conditions apply. In this case, the DTMF tones are trans-
lated by the receiver to digital data and forwarded to the mi-
croprocessor, where it is translated into further data required
by the trunk processor. The trunk processor converts this data
to the proper dial pulse train required by the CO exchange. It
should be noted that both the DTMF tones and DP signals will
appear on the trunk circuit unless "inhibit outgoing audio until
answer supervision" is returned from the CO.
8.27
The receiver is disconnected as soon as the trunk access code
.
has been detected if both the extension and trunk are DTMF
(Figure 8-3(b)) and if Toll Denial is not checked. If the extension
requires DTMF to DP conversion, the receiver is maintained until dial-
ing is completed. Toll Denial requires that the receiver be maintained
on the speech path until the required number of digits have been
dialed (see Section MITL9105/91
trol).
Dialing a Tie Trunk (From an Extension)
8.28 The circuit operations described above are similar to those
required for Tie Trunk circuits, with the following exceptions.
For DP extensions to DP tie trunk circuits (Figure 8-3(d)), the require-
ment exists to inhibit dial train distortion arising as a result of tandem
operation through one or more tie trunks. For this reason, when the
trunk processor receives the input data, it causes the output to the tie
trunk to be a regenerated train of dial pulses. It should be noted also
that the trunk processor isolates the speech path to prevent dial
pulses from feeding back to the extension.
Dialing a Trunk (From a Console)
8.29 As noted in paragraph 8.15 (Dialing Internally (From a Console)),
the console dial pad produces digital signals which are stored
by the microprocessor. After the trunk access code has been dialed,
the subsequently keyed data signals are forwarded to the micro- -
processor where, after decoding, they are forwarded to the trunk card
and outpulsed to the trunk line. Figure 8-3(e) illustrates this circuit.
Note that a receiver card is not required for this configuration.
SECTION 91 OW911 O-096:180-NA
Multi-Digit Toll Con-
Page 35