1G SFPs aren’t “all the same.” Media (fiber vs copper), wavelength, reach, connector, temperature grade, and even application domain (Ethernet, SONET/SDH, PON, Fibre Channel) all matter. Use the tables below to pick the exact 1G SFP you need—then sanity-check with the ordering checklist at the end.
How to Classify the SFP Transceivers?
SFP Media Choices (Start Here)
Media | Typical Label | Connector | Wavelength(s) | Reach (typical) | Use When |
Multimode Fiber (MMF) | 1000BASE-SX | LC duplex | 850 nm (also 1310 nm variants) | 550 m (OM2/OM3; 220–550 m by fiber grade) | Short-reach in-row/row-to-row |
Single-Mode Fiber (SMF) | 1000BASE-LX/LH/EX/ZX/EZX | LC duplex | 1310 / 1550 nm | 2 km → 160 km (see detailed table) | Campus/metro/long-haul |
Copper (Twisted Pair) | 1000BASE-T | RJ-45 | n/a | 100 m on Cat5e/Cat6/Cat6A | Use existing copper cabling; low cost/port-power |
Color cues (if present) are not universal, but many vendors use: black = 850 nm MMF, blue = 1310 nm SMF, yellow = 1550 nm SMF. Always read the label/DOM.

Fiber SFP Lineup & Distances (1G)
Product Type | Common Name | λ | Fiber | Connector | Max Distance (typical) |
1000BASE-SX-85 | SX | 850 nm | MMF | LC | 550 m |
1000BASE-SX-31 | SX-1310 | 1310 nm | MMF | LC | 2 km |
1000BASE-LX-31 | LX/LH (short) | 1310 nm | SMF | LC | 10–20 km |
1000BASE-LH-31 | LH (long) | 1310 nm | SMF | LC | 40 km |
1000BASE-EX-55 | EX | 1550 nm | SMF | LC | 40 km |
1000BASE-ZX-55 | ZX | 1550 nm | SMF | LC | 70–80 km |
1000BASE-EZX-55 | EZX | 1550 nm | SMF | LC | 120 km |
1000BASE-ZXC-55 | ZXC | 1550 nm | SMF | LC | 160 km |

Distances assume clean end-faces and compliant fiber; check link budget (Tx power – Rx sensitivity ≥ fiber loss + connector/splice loss + safety margin).
BiDi & WDM SFPs (Save Fibers or Mux More Waves)
Type | How It Works | λ (Tx/Rx examples) | Fiber/Conn | Reach (typical) | When to Use |
BiDi (BX) | Single strand; opposite wavelengths each direction | Tx 1310/Rx 1490 (U), Tx 1490/Rx 1310 (D); also 1510/1590, 1310/1550 | SMF, LC simplex or duplex | 2–160 km | Halve fiber count; deploy in matched U/D pairs |
CWDM SFP | 1 λ out of 1270–1610 nm grid | 1270…1610 (20 nm steps) | SMF, LC duplex | 20–160 km | Aggregate many 1G lambdas on one pair |
DWDM SFP | C-band ITU grid (C17–C61) | Narrow ITU channels | SMF, LC duplex | 80–100 km (+ EDFA) | High-count wavelengths over long spans |

1000BASE-T (RJ-45) SFP
Feature | Spec |
Connector | RJ-45 |
Cable | Cat5e/Cat6/Cat6A (up to 100 m) |
Speed/Auto-Neg | 10/100/1000 Mb/s |
Use Cases | Legacy copper drops, low-cost access, temporary turn-ups |
Temperature Grades (Pick for the Environment)
Grade | Range | Typical Use |
Commercial (COM) | 0 to +70 °C | Offices, wiring closets, data centers |
Industrial (IND) | −40 to +85 °C | Outdoor enclosures, factory floors, base stations |
Military (MIL) | ~−55 to +100 °C (special builds) | Harsh environments; niche availability |
Network-Switch.com typically supplies Commercial and Industrial SKUs. Ask our team if you require MIL-temperature parts.
Common SFP Variants (Don’t Mix Them Up)
Family | Nominal Rate | Typical Use | Note |
SFP | 1G | Gigabit Ethernet, 1G Fibre Channel (1GFC) | This article’s focus |
SFP+ | 10G | 10GbE, 8GFC | Same shell, different PHY, not inter-changeable with SFP |
SFP28 | 25G | 25GbE | Backward-compatible in some ports (check switch) |
QSFP+ | 40G (4×10G) | 40GbE, 4×10G breakout | Larger body (quad lanes) |
QSFP28 | 100G (4×25G) | 100GbE | Modern DC uplinks |

Brand Examples (Cisco / Huawei / Ruijie) — 1G Only
Type | Cisco | Huawei | Ruijie | Notes |
SX MMF 850 nm | GLC-SX-MMD | SFP-GE-SX-MM850 | RG-SFP-GE-SX-MM850 | ~550 m |
LX/LH SMF 1310 nm (10–20 km) | GLC-LH-SMD / GLC-LX-SMR | SFP-GE-LX-SM1310 | RG-SFP-GE-LX-SM1310 | Check 10 vs 20 km spec |
EX 40 km | GLC-EX-SMD | SFP-GE-EX-SM1310 (or 1550) | RG-SFP-GE-EX | Verify λ and budget |
ZX 70–80 km | GLC-ZX-SM | SFP-GE-ZX-SM1550 | RG-SFP-GE-ZX-SM1550 | Often needs attenuator for short links |
EZX 120 km | (various OEM labels) | SFP-GE-EZX-SM1550 | RG-SFP-GE-EZX | Long-haul carrier |
BiDi 10–40 km | GLC-BX-U/D | GE-BIDI (1310/1490) | RG-SFP-GE-BX-U/D | Order U/D as matched pairs |
CWDM 20–80+ km | CWDM-SFP-xxxx | SFP-GE-CWDM-xxxx | RG-SFP-GE-CWDM-xxxx | xxxx is λ (e.g., 1310/1470…1610) |
DWDM 80–100 km | DWDM-SFP-xxxx | SFP-GE-DWDM-Cxx | RG-SFP-GE-DWDM-Cxx | ITU channel code |
Copper 1000BASE-T | GLC-T | SFP-GE-T | RG-SFP-GE-T | 100 m Cat5e/6/6A |
Ordering Checklist
- Speed & standard match (SX/LX/EX/ZX/BX/CWDM/DWDM/1000T)
- Fiber type & connectors (MMF vs SMF; LC duplex vs simplex; RJ-45)
- Wavelength pair correct (BiDi U/D matched; CWDM/DWDM channel code)
- Distance vs link budget (include connectors/splices; add attenuator if needed)
- Temperature grade (COM vs IND), DDM/DOM monitoring supported
- Switch compatibility (platform/OS, vendor allow-list, DOM readouts)
FAQ
Q1: Can I plug an SFP into an SFP+ (10G) port?
A: Some switches allow it (port downshifts to 1G), others don’t. Check your platform’s datasheet.
Q2: Do BiDi SFPs work with standard duplex SFPs?
A: No. BiDi must be deployed in complementary pairs (U ↔ D) on the same single fiber.
Q3: Why do ZX/EZX optics need an attenuator at short distances?
A: Their transmit power is high for long spans; at short links, received power can exceed Rx max. Add the vendor-recommended dB pad.
Conclusion
Pick the SFP by medium (MMF/SMF/copper), wavelength & reach, and environment—then verify with a link budget and your switch’s compatibility. Use BiDi to halve fibers, CWDM/DWDM to scale wavelengths, and industrial-temp SKUs for outdoor/harsh sites. With these tables and the checklist, you can build a 1G plan that just works.
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