Grandstream F-MM850-550M-1.25G SFP Fiber Module

The Grandstream F-MM850-550M-1.25G is a Gigabit SFP transceiver for multi-mode fibre, running at 850 nm over distances up to 550 m.

This is the everyday in-building fibre module: five and a half times what copper manages, at the speed most links actually need. A riser between floors, a run to a cabinet at the far end of a warehouse, a link to an outbuilding across the yard — all comfortably inside 550 m, and none of them needing ten gigabits.

Buy them in pairs. A fibre link needs a module at each end, and both ends must match — same fibre type, same wavelength, same speed. A multi-mode module will not talk to a single-mode one, and mismatched ends are the most common reason a fibre link fails to come up on the day.

Key features

• 1.25 Gigabit SFP transceiver
• Multi-mode fibre, 850 nm
• Up to 550 m
• Genuine Grandstream module — matched to Grandstream switch SFP slots

Works with

• GWN7803 — four SFP slots
• GWN7801 — two SFP slots
• F-MM850-300M-10G — multi-mode at 10G, 300 m
• F-SM1310-20KM-1.25G — single-mode for between sites
• Grandstream GWN switches

Frequently asked questions

Do I need one or two?

Two — one at each end of the fibre. Ordering one is an easy mistake and it stops the whole job.

Multi-mode or single-mode — which do I need?

Multi-mode for runs inside a building or across a site; single-mode for runs between separate sites. If the fibre is already installed the choice is made for you — the module must match the glass.

Why fibre rather than copper?

Distance first — copper stops at 100 m and this reaches 550. Interference second: fibre carries no electricity, so it is immune to the electrical noise in a factory and it isolates the two buildings electrically, which matters in a thunderstorm.

Would 10G be better?

Only if the link actually needs it. Most in-building runs carry phones, cameras and file access, which is nowhere near a gigabit. The 10G module costs more and often changes nothing.

Will it work in a non-Grandstream switch?

Often, but some switches only accept their own vendor's coded modules. If the far end is another brand, check its compatibility list before ordering.

Planning a fibre link? Call 0333 242 1314 or email sales@clisecure.com — tell us the distance, the fibre type and the switches at both ends and we will match the modules.