On Toshiba Strata PBX systems (specifically the CHSUB672A), a handset's message waiting indicator (MWI) can get stuck blinking even when there are no voicemails.
The fix:
- Pick up the handset
- Dial
#408 - Hang up
This sends a message waiting indicator reset command to the station, clearing the phantom notification.
Why it happens: The PBX sends MWI signals via in-band signaling. If the voicemail system crashes mid-message, disconnects unexpectedly, or the integration link between the VM and PBX drops, the "on" signal gets sent without a corresponding "off" signal.
Historical note: Toshiba exited the telecom business in 2017. If you're still running Strata systems, plan your migration — parts and support are increasingly scarce. Modern alternatives like Microsoft Teams Phone, Cisco Webex Calling, or cloud PBX solutions eliminate these hardware-level quirks entirely.