CompactPCI cont..
Computer Telephony
An important application for CompactPCI technology is Computer Telephony (CT).
This rapidly growing industry is very innovative, and equipment suppliers are constantly
looking for higher performance and competitive advantages. CompactPCI’s rear panel
I/O capability and excellent Mean-Time-To-Repair (MTTR) characteristics are proving
ideal for CT applications.
Many telephony systems have been built with commercial desktop PC’s because they
offer high performance at low cost. But reliability is generally poor. They have little
airflow, a limited number of expansion slots, awkward cabling, and take a long time to repair.
Product stability is minimal or non-existent, which is often a problem for real time
applications like telephony that need predictable performance. Passive backplane PC’s
improve the situation somewhat, and are a popular choice for telephony, because they
typically offer more slots, bigger power supplies to support power hungry DSP voice
boards, and have longer product lifetimes. But they are still hard to repair, and
secondary voice buses run through the voice boards make these systems a rat’s nest of
failure-prone flat cables.
Developed at the request of the telephony industry, the CompactPCI Computer
Telephony Specification (PICMG 2.5) combines the core CompactPCI spec with a
new, industry standard voice bus known as H.110 wired on the backplane in parallel
with the PCI bus. By designing to this new specification, telephony suppliers enjoy the
ruggedness and simple repair offered by CompactPCI and a new, high performance
voice bus supported by major voice board suppliers. Flat cables are eliminated and high
density line cards providing up to 16 T1/E1 lines connected through rear panel I/O are
possible.
Many Choices
One of the most powerful characteristics of CompactPCI is its processor independence.
Since virtually all high performance microprocessor architectures use PCI, a wide range
of CompactPCI processors boards – and an even wider range of applicable operating
systems - are available. CPU’s built with Intel architecture (Pentium, Pentium II, K6) are
good engines for Windows 2000, which is increasingly popular due to its powerful
software development tools and standardized application interfaces. Applications
needing a real time operating system like LynxOS or VxWorks or 64-bit operation are
using fast, low power PowerPC RISC processors.
Figure 2: MCP750 PowerPlus Architecture Single-Board Computer
Boards or Boxes
As equipment builders move to outsource more of the embedded computer portion of
their product, CompactPCI suppliers are providing not just boards. They are delivering
full systems that include CPU, chassis, backplane, power supply, peripherals, and
operating system. This trend is a permanent one, as telecom and telephony suppliers
concentrate on their added value and streamline their development schedules and costs.
What’s Next
The developments around CompactPCI have been fast and furious in the last 24 months,
and show no signs of slowing down. 11 authorized PICMG subcommittees are working
on further extensions to the core spec to provide specific functions for specific
applications. Like the Hot Swap and Computer Telephony specs, these are optional
extensions to a stable core specification. The specs under development include
standardized mezzanine pin-outs, combining VMEbus and CompactPCI, System
Management Bus, and bridging strategies for large systems.
As the adoption of CompactPCI by the telecom and telephony industries continues, High
Availability (HA) multiprocessor architectures and robust fault tolerant systems will
certainly be developed using CompactPCI. Additional special purpose sub-buses like
ATM will provide tremendous data communications bandwidth for the inevitable
convergence of data, voice, and video.
CompactPCI technology is an important building block for the future, which looks very
bright. |
