Hardware Platforms for Computer Telephony The FAR Voice

From Standard PC's to Fault Tolerant Systems

FAR Systems equipment uses industry standard ISA bus computers. Though small systems are usually implemented using a PC motherboard to save money, other options are available as needed or required for larger systems.

FAR Systems offers three series of computer platforms, all rack mounted units, from a standard PC motherboard to fault tolerant systems with 20 board slot capacities. The rack mount chassis make multi-chassis systems easier to integrate.

Series 1500 PC Motherboard Systems top of page

This entry level system is a rack mount unit which uses a standard PC motherboard. Since telephone interface boards are mostly high density, full length boards, the use of a PC chassis is not recommended because of relatively poor cooling. The 1500 chassis uses a PC motherboard to save money, but the rack mount design provides superior cooling and a shock mounted disk bay. However, because of the use of a PC motherboard, this chassis has very limited expansion capability.

Series 2500 Passive Backplane top of page

When a system requires more board slots than can be provided on a PC motherboard, a 14 slot passive backplane system is used. In a normal PC the processor, memory, and other chips that comprise the computer section (i.e., everything except the peripheral cards, such as telephone interface cards, network cards, etc.) are contained on the motherboard. The motherboard also contains the connectors into which the peripheral cards are inserted. In a passive backplane system, the backplane contains no active circuitry, just connectors (lots of them), hence its name. A separate CPU card plugs into this backplane, just as do the peripheral interface cards, thus also providing a very superior mean-time-to-repair.

Series 3500 Fault Tolerant top of page

Power supplies and disks are the most failure prone parts of a computer system. To attain the highest reliability, a system should be built with mirror disks and dual redundant power supplies.

The series 3500 platform is a must for mission critical applications. It is built on a special rack mount chassis system with dual, redundant, hot-pluggable power supplies. These chassis provide the ultimate in fault tolerant platforms. The 3500 chassis is also equipped with a comprehensive alarm system that monitors power supply voltages, fan rotation, and internal temperature. The alarm sub-system provides an audible alert, and it can also be coupled to a remote alarm notification package that provides remote signaling of all alarm conditions, including software errors.

Mirror Disk System top of page

As noted above, the disk, as a mechanical item, is one of the failure prone parts of a computer system. Disks can be made virtually immune to being the weak link in a system by providing a mirror disk.

This dual disk system uses a special controller that automatically utilizes two disks. Writes are made automatically to both disks. If the primary disk fails, data is read automatically from the secondary disk and the data on the primary one are repaired. If failures happen too often, operation is transferred to the secondary disk and an audible alarm is sounded.

Mirror disks can be installed in any of the platforms.