nader@amdcad.AMD.COM (Nader Vijeh) (12/12/89)
Several recent articles have referred to the 100m maximum distance limita- tion of the 10BASE-T networks. The 100m limitation is based on the worst case attention of the Multi-pair PVC insulated 0.5mm, 24 gauge, cable. There is however no `length' limitation set in the 10BASE-T standard. The standard however refers to Insertion Loss (<11.5 dB at all frequencies between 5.0 and 10 MHz) and maximum propagation delay, which is set to 1000ns with the provision that propagation velocity should be 0.585c mini- mum. Any twisted pair cable that meets these requirements and the Differen- tial Characteristic Impedance (100 Ohms nominal), and also meets Medium Timing Jitter budget may be used for 10BASE-T networking. Using the 0.585c and the 1000ns maximum delay would allow 175m of cable with 6.5dB/100m attenuation to be used. It is therefore possible to use the pre-installed telephone wiring for <100m runs and install better quality cable for longer runs. -------------------------------------------------------------------------- Disclaimer: The above is based on my interpretation of the draft 10BASE-T Standard. --------------------------------------------------------------------------