3Com 3CB9LF20MM Switch 4007 / 4007R Switch / Carrier Ethernet Line Card

The 3Com 3CB9LF20MM is a 20-port 100Base-FX switching module for the 3Com Switch 4007 and Switch 4007R modular chassis (also relabelled by HP as JF027A). It fits into a chassis expansion slot and provides twenty MTRJ fibre Fast Ethernet ports, giving network teams a way to extend fibre connectivity across a Switch 4007 deployment without adding a separate standalone fibre switch.

The Switch 4007 platform was 3Com’s Layer 2/3 modular chassis for enterprise and carrier-class networks, supporting a mix of copper and fibre line cards to match a site’s cabling plant, and the 3CB9LF20MM is one of the fibre-focused modules used to build that mix out. Each port operates at 100 Mbps over multimode fibre using MTRJ connectors, suited to building or campus backbone links where copper distance limits are a constraint. The module is hot-swappable in a live chassis, so it can be added or replaced without a full outage.

It’s a good match for sites maintaining an existing 4007 estate who need matching fibre modules for expansion or replacement. Tech-Star (UK-based, shipped worldwide) checks every module before it ships. Get in touch to confirm compatibility with your chassis configuration.