HPE 100GB QSFP28 MPO SR4 100M Xcvr - 845966-B21

HPE 845966-B21 100G QSFP28 MPO SR4 Multi-Mode Fiber Transceiver

Overview

The HPE 845966-B21 is a 100G QSFP28 MPO SR4 optical transceiver designed for short-reach 100 Gigabit Ethernet links over multi-mode fiber. Operating at 850 nm with an MPO connector interface, it delivers up to 100 m of reach on OM4 multi-mode fiber — the practical distance for inter-rack and top-of-rack-to-aggregation runs inside a data center or high-density switching environment. If your structured cabling plant is already MPO-terminated, this module drops directly into the infrastructure without re-termination. The QSFP28 form factor keeps port density high on compatible HPE networking and server platforms without dedicating chassis real estate to lower-density interfaces.

Compatibility

The 845966-B21 is keyed for HPE data center switches and server platforms that accept QSFP28 form-factor modules. Verify your target switch or HBA model explicitly lists QSFP28 SR4 support in its transceiver compatibility matrix — HPE platforms with QSFP28 cages are generally found in the FlexFabric, Arista-OEM, and ProLiant server NIC product lines. The MPO interface requires MPO-12 or MPO-8 (with appropriate pinout) multi-mode fiber patch cables — confirm polarity (Method A/B/C) before ordering pre-terminated MPO trunks. This module is intended for multi-mode plant only; it is not compatible with single-mode fiber or LC duplex cabling without an adapter, and 850 nm SR optics will not function over OS1/OS2 single-mode runs regardless of distance.

Installation Notes

Module dimensions are 18.35 × 72.7 × 8.5 mm and weight is 36.3 g — standard QSFP28 mechanical envelope, no special tooling required for insertion. Seat fully until the latch clicks; partial seating causes intermittent link faults that are difficult to diagnose at 100G. Clean MPO ferrules with a lint-free pen cleaner before mating — contamination at the MPO interface is the leading cause of insertion-loss margin failures on SR4 links. Maximum channel distance is 100 m; plan your fiber runs with slack loops and patch lengths included in the total budget.