MT8982
Applications
ISO-CMOS
ST-BUS to GCI Conversion
The MT8982 MiniDX may be used to provide a
gateway between MITEL's ST-BUS family of
components and an architecture which utilizes the
General Circuit Interface (GCI) operating at 2048
kbit/s (Figure 8). The MT8982 performs automatic
adaptation of the different frame pulse signals. The
master frame pulse to the MT8982 can be supplied
either by the ST-BUS or the GCI components. The
MT8982 will then provide either a delayed or
advanced frame pulse to the other components as
shown in Figures 9 and 10.
When an ST-BUS component is supplying the master
frame pulse (F0i), the MiniDX will supply the output
frame pulse (F0o) delayed by five channels. This
ensures that frame integrity is maintained between
the ST-BUS and GCI components. When a GCI
component supplies the master frame pulse (F0i),
F0o is advanced by five channels.
Figure 8 shows a block diagram of a GCI to ST-BUS
conversion circuit. External inversion of the clock
signal is required between the ST-BUS and GCI
components because the ST-BUS and GCI master
C4 clocks use different edges to mark bit boundaries.
To program a connection between a ST-BUS channel
and a GCI channel, some channel conversion is
necessary.
Figure 11 shows the relationship
between the ST-BUS basic access frame and the
GCI basic access frame. Because the MT8982 shifts
the GCI frame pulse (input or output) by five
channels, all of the GCI channels must be
incremented by five to be correctly addressed by the
Digital Key Telephone System
Figure 5 shows a block diagram of a Digital Key
Telephone System (DKTS) implemented with the
MT8982.
This DKTS can support up to 64
connections organized in any combination of
subscriber lines or trunks. A very small system
consisting of six lines and one trunk can very easily
and economically be designed on one board. The
MT8982 significantly reduces the tracking and board
space required for competitive switch matrices.
Distributed Switching System
The MT8982 can be used to distribute switching
capability in a very large system. In Figure 6 the
MT8982 is shown with the microport in serial bus
mode. This allows the central microprocessor to set
up and tear down connections at the remote
locations by programming the remote MT8982's
through their CSTi pins. A microcontroller in each
remote switch would not be required.
Primary Rate Serial Controller
Figure 7 shows the MT8982 used in a primary rate
serial control application. The MT8982 is used as
the control interface from a microcontroller to
MITEL’s MH89760/790 T1 Primary Rate Interfaces
using the microcontroller’s serial microport. The
MT8982 offloads signalling and trunk control
functions from the central switch matrix leaving more
capacity for switching.
CENTRAL DKTS CONTROLLER
To
Central
Office
MT8972
DNIC
MT8982
MiniDx
MH88630/1
C.O. Trunk
MT8972
DNIC
•
•
•
MT8972
DNIC
Microcontroller
Figure 5 - Digital Key Telephone System (DKTS)
2-38
MITEL [ MITEL NETWORKS CORPORATION ]
