Advance Information
MT89L85
ISDN Desktops
(2B+D)
••••••
Analog Connections
••••••
Server 2
Server 1
T1
••••••
T1
E1
Access to
Public
Network
Server 3
T1/E1
Isochronous Network
Server 4
n x 64
Connections
(e.g. Video)
Figure 8a - Private Isochronous Network
predictable data transfer delays that can be
implemented at a reasonable cost. The Low Latency
Isochronous Network is one of the alternatives that
system designers have chosen to accommodate this
requirement (see Figure 8a). This network can be
implemented using existing TDM transmission media
devices such as ISDN Basic (S or U) and Primary
rates trunks (T1 and CEPT) to transport mixed voice
and data signals in grouped time slots; for example,
2B channels in case of ISDN S or U interfaces or up
to 32 channels in case of a CEPT link.
Figure 8b shows a more detailed configuration
whereby several PCs are connected to form an
Isochronous network. Several services can be
interconnected within a single PC chassis through
the standardized Multi Vendor Integration Protocol
(MVIP). Such an interface allows the distribution and
interconnection of services like voice mail, integrated
voice response, voice recognition, LAN gateways,
key systems, fax servers, video cards, etc.
The information being exchanged between cards
through the MVIP interface on every computer as
well as between computers through T1 or CEPT links
is, in general, of mixed type where 64Kb/s and
N*64Kb/s channels are grouped together. When
such a mixed type of data is transferred between
cards within one chassis or from one computer to
another, the sequence integrity of the concatenated
channels has to be maintained. The MT89L85 device
suits this application and can be used to form a
complete non-blocking switch matrix of 512 channels
(see Figure 9). This allows 8 pairs of ST-BUS
streams to be dedicated to the MVIP side whereas
the remaining 8 pairs are used for local ancilliary
functions in typical dual T1/E1 interface applications
(Figure 10).
Another application of the MT89L85 in an MVIP
environment is to build an ISDN S-interface card
(Figure 11). In this card, 7 pairs of ST-BUS streams
are connected to the MVIP interface while the
remaining pair is reserved for the interconnection of
MITEL MT8930 (SNIC), MT8992 (H-PHONE) and
the MVIP interface.
9
MITEL [ MITEL NETWORKS CORPORATION ]
