Mitel SX-200 Documentation page 473

SECTION 9105/9110-096-l 80-NA
Page 34
8.21 Meanwhile, if the extension had flashed out of a conference, the
conference is unaffected. However, if the other party was not in
conference, it is disconnected from its speech path and connected
instead to the HOLD junctor, which is a speech path with a low
impedance such that it effectively "grounds" the output of any exten-
sion or trunk connected to it, thus preventing parties on the HOLD
junctor from hearing each other.
Incoming Calls (GS/LS
8.22 When the trunk circuit detects ringing voltage, or forward or
reverse current, or a tip ground (ground start trunks), the trunks
microprocessor interrupts the system processor via the IZ/Scanner
arrangement (see paragraph 8.09, Off-Hook (Console)) and lights up
the LED on the trunk card. The system tlien reads a status report from
the trunk.
8.23 The system processor finds and tests a speech path (see para-
graph 8.04, Speech Path Accessing) and notifies the pro-
grammed equipment (console or extension). When it answers, the sys-
tem processor connects it and the trunk to the speech path and sends
a data line command to the trunk card. The trunk card then terminates
the trunk circuit and enables the audio.
If the trunk has been programmed for DISA, the system proces-
8.24
sor waits 10 seconds before answering and then connects a
receiver and a dial tone generator. This allows the trunk to appear as (. ,
though it were an extension and enables it to dial internal stations and
features (see paragraph 8.10, Dial Tone (Extension) and paragraph 8.12,
Dialing Internally (From an Extension)).
Dialing a CO Trunk (From an Extension)
8.25 When an extension has gone off-hook and is connected to dial
tone and a receiver (see paragraph 8.10, Dial Tone (Extension)
and paragraph 8.12, Dial Internally (From an Extension)), an access
code is dialed to obtain a CO trunk. Upon determining the validity of
this code, the processor interrogates the trunk circuit cards to find an
available trunk in the appropriate trunk group. A data line seize com-
mand is then sent to the trunk's microprocessor
is connected to the extension's speech path (see Speech Path Ac-
cessing). If the trunk is "ground start", the ring lead is grounded and
the trunk's processor waits for CO acknowledgement. The trunk pro-
cessor connects the audio network and enables the au.dio and the LED
on the circuit card.
8.26 There are three basic configurations of Extension/Trunk Circuit
conditions which are encountered as follows:
DP extension accessing a DP trunk
l
DTMF extension accessing a DTMF trunk
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DTMF extension accessing a DP trunk
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These three combinations result in a number of system connection
Trunks)
and the trunk circuit
. , '