GN Netcom 9120 Replacement Battery 3.7V 340mAh 14151-01

GN Netcom 9120 / 9125 — 3.7V Li-Polymer Replacement Battery (14151-01)

This 3.7V, 340mAh lithium-polymer cell replaces the OEM pack in the GN Netcom 9120 and Netcom 9125 wireless DECT headsets. It matches the original 14151-01 specification and fits the compact housing without modification. Swap it when the original cell no longer holds enough charge to get through a full shift.

• Netcom 9120 and 9125 compatibility: Both headsets run the same 3.7V architecture, use the same connector footprint, and communicate with the base station through the same BMS handshake protocol — one cell covers both models.
• Bench tested on actual hardware: We cycled this pack through the Netcom base station and confirmed the BMS handshake completes correctly, the charge indicator advances as expected, and the cell holds voltage through sustained DECT radio and audio draw without premature cutoff.
• First-cycle base station registration: Place the headset in the base station and allow a complete charge cycle before taking any calls. The Netcom base logs the new cell during this cycle and calibrates the talk-time indicator — skipping it leaves the display inaccurate for the first several uses.

Base station not recognising the new pack after fitting

The Netcom 9120 base station uses a BMS handshake to verify the installed cell before it begins a charge cycle. If the pack was stored for an extended period, its resting voltage may have dropped below the threshold the base expects on initial contact — typically under 3.0V. The base interprets this as a fault rather than a discharged cell and shows a charging error or no indicator at all. Reseat the headset firmly in the cradle and leave it undisturbed for 15 minutes; the base trickle-charges the cell until it crosses the recognition threshold, then switches to normal charge mode.

Headset cutting out mid-call on the new battery

The Netcom 9120 draws current from two simultaneous loads — the DECT radio transmitter and the audio amplifier. Under that combined draw, a cell that has not completed its first conditioning cycle can show a sharp voltage sag and trigger the BMS undervoltage cutoff, dropping the headset off the line. This is not a faulty cell. Run three to five full charge-and-use cycles through the base station and the cell's internal resistance settles, reducing the sag. If cutouts continue past the fifth cycle, measure resting voltage after a full charge — it should read at or above 4.1V.