MT90880/1/2/3
Data Sheet
25
Zarlink Semiconductor Inc.
4.6 H.100/H.110 Extension
The H.100/H.110 TDM bus commonly used in today’s computer telephony systems is based on a physical
backplane the width of a single telecom rack. Extending the reach of the bus is expensive using traditional TDM
infrastructure. Such links are not easily scalable, and require accurate and stable clock generation.
An MT9088x device enables the bus to be simply and easily extended beyond confines of the rack using an
Ethernet connection over simple twisted pair cable. This enables the entire bus to be replicated in another physical
location using a low cost but flexible and easily managed connection medium (see Figure 7).
Figure 7 shows the MT9088x device connected to a TDM backplane via a TDM switch device (e.g. the Zarlink
MT90866). This is used to concentrate the backplane onto the TDM interface of the MT9088x. The configuration
allows any of the TDM channels on the original backplaneto be switched onto any channel on the extension
backplane, and vice-versa.
Figure 7 - H.100/H.110 Extension over Ethernet link
4.7 H.100/H.110 Expansion
One of the issues faced by medium and high-end telecommunication systems is scalability. The H.100/H.110
TDM bus is limited to 4096 concurrent timeslots, or 2048 full duplex links. The MT9088x family can be used to
expand the capacity of a system by switching timeslots between multiple separate H.100/H.110 bus segments.
This application is shown in Figure 8. Unlike parts based on expensive or proprietary infrastructure, the use of
an Ethernet switch fabric enables common, readily available network hardware to be employed, reducing both
installation and operational costs.
As in Figure 7, the MT90866 TDM switch is used to concentrate the TDM backplane onto the MT9088x TDM
interface. This allows any channel on a bus segment to be switched onto any channel on any other bus
segment.
Original
H.100/H.110
bus segment
MT90866
H.110
Switch
MT90880
TDM-IP
Processor
Extension
H.100/H.110
bus segment
MT90866
H.110
Switch
MT90880
TDM-IP
Processor
Ethernet
transparent data flow