7 May 2003 Arlington, VA Lightwave -- A recently completed addendum to TIA/EIA-785 Short Wavelength Fast Ethernet Standard makes it possible to further reduce horizontal cabling costs for multimode fiber networks. Addendum #1 to the standard removes the receiver bandwidth specification, eliminating unwarranted limitations in transceiver designs and potentially expanding available transceiver and manufacturer choices, say TIA representatives. Since transceivers are one of the most expensive components in a fiber port, this addendum should enable network managers to lower the costs of their fiber-based systems.
The bandwidth specification was removed after the F.O. 4.2 working group (formerly F.O. 2.2) performed extensive simulation and link testing and determined that the receiver bandwidth specification was technically redundant with the specification for stressed receive sensitivity.
Originally ratified in May 2001, TIA/EIA-785 marked an important development for network planners seeking a cost-effective migration path from 10-Mbit/sec Ethernet to 100-Mbit/sec Fast Ethernet. "This was a trend-setting fiber standard," asserts John Struhar, Chair of the TIA Fiber Optics LAN Section (FOLS). "It provides a cost-effective migration path for network managers by supporting data communications between legacy 10-Mbit/sec fiber LAN optoelectronics and a new generation of less expensive short wavelength 10/100-Mbit/sec-capable products (parallel detection) or between two link endpoints comprising 100BASE-SX capable products (auto-negotiation)."
Previously, the only operating wavelength for 100-Mbit/sec Fast Ethernet (100BASE-FX) was 1300 nm, making it incompatible with 10-Mbit/sec Ethernet Systems (10BASE FL), which operate at 850 nm. When 100-Mbit/sec Fast Ethernet was first developed, it was considered a backbone technology, so the discrepancy in wavelengths was not an issue. However, as 100-Mbit/sec fiber Ethernet began to be deployed to the desktop, the lack of interoperability and migration path slowed the deployment of fiber networks.
Struhar also explained that the standard supports a minimum 300-meter link length, which means that conforming products also support horizontal cabling subsystems as specified in the TIA/EIA-568-B.1, building cabling standard, whether using the traditional hierarchical star architecture or the newer centralized fiber-optic cabling systems.
The standard is available from Global Engineering by calling 1-800-854-7179 (U.S. and Canada), outside the U.S. at 1-303-397-7956 or from their website at http://global.ihs.com.