Communications Cables Revised: 04.08.00
MHz vs Mbps for Common LAN Systems Reason for Revision: New page

This page presents a comparison of the operating frequency of common LAN systems vs the rate of data throughput. Many people assume there is a one-to-one relationship and that a 100 Mbps Ethernet LAN is operating at 100 MHz. While this is true in some cases, it is not so for most of the faster, latest generation LAN protocols being deployed.

The electronics of a LAN system use various techniques to subdivide the Hertz cycle into smaller chunks that can be interpreted as bits. This is generally called bit-encoding. Packing lots of bits per Hertz using bit encoding allows comparatively low frequency levels to be used for the data throughput achieved.

LAN System Protocol Operating Frequency Data Throughput Minimum Cabling Performance
Token Ring IEEE 802.5 4 MHz 4 Mbps CAT 3
10BaseT Ethernet IEEE 8802.3 10 MHz 10 Mbps CAT 3
Token Ring IEEE 802.5 16 MHz 16 Mbps CAT 5
100BaseT (Fast) Ethernet IEEE 802.3 31.25 MHz 100 Mbps CAT 5
ATM ATM 38.75 MHz 155 Mbps CAT 5
1000BaseT (Gigabit) Ethernet IEEE 802.3 about 65 MHz 1000 Mbps CAT 5e


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