Aruba J4858D — 1000BASE-SX SFP (850 nm, MMF, up to 550 m)

What it is: A 1 GbE SFP transceiver for multimode fiber (MMF) using an 850 nm VCSEL laser. It runs 1000BASE-SX over duplex LC and supports DOM/DDM (digital diagnostics). The classic short-reach optic for in-building uplinks and stack/interconnect links.

Why buyers pick J4858D (plain English)

• Cheapest way to do 1G fiber inside buildings—ubiquitous and easy to stock.

• Drop-in SFP footprint for Aruba/HPE switches with SFP slots; standard LC patching.

• Live optics telemetry with DOM (Tx/Rx power, temp, voltage) for quick troubleshooting.

60-second spec box

Optics & reach

• Wavelength: 850 nm (VCSEL)

• Fiber / connector: MMF, duplex LC

• Max distance (typical):

  • 50/125 µm (OM2/OM3/OM4): up to 550 m

  • 62.5/125 µm (OM1): up to 220 m

Line rate & standards

• 1.25 Gbps line rate (Gigabit Ethernet)

• IEEE 802.3z 1000BASE-SX, SFP MSA compliant

• DOM/DDM supported

Optical performance (typical ranges)

• Transmit power: about –9 to –3 dBm

• Receive sensitivity: to around –17 dBm

• Link budget: ~8–10 dB (ample for patch panels in-building)

Electrical / power

• Supply: 3.3 V

• Module power: ~0.8–1.0 W

Environment

• Operating temp: 0 to +70 °C (commercial)

• Form factor: hot-pluggable SFP

Where it fits (and when to choose something else)

• Perfect for: access-to-distribution uplinks, IDF↔MDF, cross-room/campus-closet runs within ≤550 m on modern MMF.

• Use J4859D (LX, 1310 nm) for single-mode runs up to 10 km.

• Use copper SFPs / DAC for very short, in-rack connections at the lowest cost/power.

Quick design tips (no-regret)

• Match fiber type to distance: 50 µm MMF (OM2/OM3/OM4) gives full 550 m; 62.5 µm (OM1) tops out near 220 m.

• Budget the link: include patch panel and connector losses (≈0.3–0.5 dB each).

• Clean LCs before testing: most “mystery” errors are dirty ferrules.

• Label both ends (port, wavelength, distance) to avoid mixing with LX optics.

TL;DR

J4858D = 1G SFP, 850 nm, MMF, LC duplex, up to 550 m (50 µm) / 220 m (62.5 µm) with DOM. It’s the reliable, drop-in 1000BASE-SX optic for short-reach fiber uplinks inside buildings.