' Tl Trunkcard; Brief Description; Facilities; Generaldescription - Mitel SX-200 Practices

16
' Tl TRUNKCARD
Brief Description
16.4 The Tl Trunk Card interfaces a single Tl trunk circuit to the SX-,200 DIGITAL PABX and the
SX-2UUFD. The Tl protocol is used primarily in North America. The Tl Trunk Card is
not available with Generic 1001 or Generic 1002,
Facilities
16.2
The Tl Trunk Card provides the following facilities:
l
Tl Clock - System Clock Phase Comparator
l
Bidirectional Tl to ST-BUS data rate and format conversion
l
Line Equalization.
General Description
16.3 The Tl interface will transmit and receive 24 6-bit voice/data channels on a 4-wire
digital trunk operating at I.544 Mb/s. The Bay Controller performs all control
functions.
To provide signaling information on the Tl line, data bits are "stolen" from each channel
to provide channel associated signaling,
The Tl Trunk Card includes a phase comparator which, through the Tl Clock Module
on the Main Control Card, keeps the system clock in phase with the incoming frame
rate clock. This prevents data losses due to clock rate differences. (Refer to Main
Control Card /Tl Clock Module in this Section). Phase Error is the difference between
the clock rate received on the link and the clock rate generated within the system (if the
Tl clock module is being adjusted to the incoming clock rate). If the difference climbs
by greater than 1 in a single reading then the next three readings
are filtered out. If the
fourth reading has climbed greater than I then the link is considered unstable. A
maintenance log is generated and the link is no longer used as a network
synchronization source.
The SX-ZOO DIGITAL system supports a maximum of one Tl Trunk Card per digital
bay, In 336 or 466port systems Bay 2 supports only one Tl Trunk Card.
The SX-200 FD system supports a maximum of one Tl Trunk Card per Peripheral
Cabinet or bay. The Tl Trunk Card cannot be installed in the first Peripheral Cabinet
One incoming Tl trunk is selected as the primary timing source; the system locks its
PCM clock and all other Tl trunk cards in the system to this incoming data stream.
9109-096-125-NA Issue 1
Revision 0 125 16-I