10G SFP+ and 1G SFP Transceivers: Reading the Part Number
SFP and SFP+ share a cage and a physical size but are two different speeds — 1G and 10G. The part number after the generic name is what tells you which of those, at what reach, and on which fibre. Reading it correctly is most of the work in buying the right module.
The four things a part number encodes
- Speed — SFP is 1G, SFP+ is 10G, SFP28 is 25G, QSFP28 is 100G. A 1G module in a 10G-only port is a common and silent mistake.
- Reach class — SR (short reach, multimode), LR (long reach on single-mode), ER and ZR progressively longer. The letters are a reach class, not a vendor preference.
- Wavelength — 850 nm for multimode SR, 1310 nm for LR, 1550 nm for ER/ZR and for DWDM channels.
- Vendor coding — the part prefix belongs to whoever coded it. The same optical engine ships under different prefixes for different platforms.
Where buyers get caught
- Platform coding. Many switches only accept modules coded for their brand. If you are buying for a specific platform, the platform matters more than the module’s generic name.
- MMF versus SMF. SR needs multimode; LR needs single-mode. Both ends of a link have to match, including the patch cords already in the tray.
- Industrial temperature range. Cabinet and pole-mounted equipment needs the extended-temperature part, not the commercial one.
- Quality tiers. OEM, compatible-new and serviceable-used all exist on the market at very different prices. We state which one a quotation is for, so the comparison is honest.
Tell us the platform and the link length and we will narrow the catalogue to the modules that actually fit, including apples-to-apples alternatives at different price points.