Chapter 5: Specifications
5-6 HSIM-F6 User’s Guide
5.4 CABLE SPECIFICATIONS
The FDDI Physical Layer Medium Dependent (PMD), Twisted Pair
Physical Layer Medium Dependent (TP-PMD), and Single Mode Fiber
Physical Layer Medium Dependent (SMF-PMD) ANSI standards define
cable requirements as follows:
Multimode Fiber
Core diameter: 62.5 µm nominal
Cladding diameter: 128.0 µm maximum
122.0 µm minimum
Cable attenuation: ≤ 2.5 dB/km typical
Single Mode Fiber
Core diameter: 8.7 µm +/- 0.5 µm
Cladding diameter: 127.0 µm maximum
Cable attenuation: ≤ 0.5 dB/km typical
5.4.1 Multimode Fiber Optic Cable Length
The PMD FDDI standard specifies the following:
Maximum total cable length: 100 km (62 miles) — dual ring
200 km (124 miles) — wrapped
Maximum multimode cable length
between adjacent nodes: 2 km (1.2 miles)
5.4.2 Single Mode Fiber Optic Cable Length
The SMF-PMD FDDI standard specifies the following:
Maximum total cable length: 100 km (62 miles) — dual ring
200 km (124 miles) — wrapped
Single mode cable length
between adjacent nodes: 40 km (24 miles) maximum
25 km (15 miles) typical