How to extinguish the flashing light on a NEC SL or SV Telephone System.

How to extinguish the flashing light on a NEC SL or SV Telephone System.


Please note - the advice offered is for systems installed in the United Kingdom. The feature codes and/or lamp colours mentioned may not necessarily apply to systems installed elsewhere in the world. If these instructions do not resolve your particular issue contact the dealer who installed your system via their support channels.

The purpose of the flashing lamp is to inform you that you may have new voice mail, or that another user has activated message waiting on your phone.

What colour is the flashing light?

  1. If the light is flashing red, it means you have a voicemail in your personal mail box.
  2. If the light is flashing green, it means someone has set a Message Waiting notification on your phone.
  3. If the light is steady green, it means you have set a Message Waiting notification for someone else.

To listen to voicemail: 

If you have any unread voice messages, the quantity of voice messages will be displayed on the screen. E.g. "VM:04" will indicate you have 4 messages in addition to the flashing light.

On most SL1100 or SL2100 systems, your voice mailbox can be accessed by pressing the “VM” soft key.

Soft keys are buttons where the function changes depending on the state of the phone (off-hook / on-hook / call in progress etc). Soft keys typically use part of the main display to identify their current function and are usually located in a row immediately beneath the main display.

If your phone is not equipped with a "VM" soft key the mailbox can be accessed either by dialling *8 or 717 (depending on the numbering plan assigned to the system during installation).

Once connected to your voice mailbox, the mailbox can be managed either by using the available soft keys or by following the audio prompts in a similar fashion to a mobile phone voice mailbox. Once all of the messages have been acknowledged, the light will turn off.

To cancel Message Waiting

Message waiting is a feature available on internal calls. This feature allows a caller dialling another extension to leave a “message waiting” notification on the phone of the person being called.

To set message waiting, the caller dials a particular extension. Pressing 0 or the “MW” soft key whilst listening to ring back / busy tone will activate the message waiting lamp on the extension being called.

Message Waiting can be cleared by several methods:
  1. Pressing the "Exit" button ("Clear" button on some models) and selecting "MW" followed by "Yes" will clear a Message Waiting notification that you may have set on another users handset (steady green lamp)
  2. Dialling *0 will reply to another users request (flashing green lamp)
  3. Alternately feature code 873 could be used which will cancel Message Waiting without replying.

Common Cancel

If none of these methods work for you, try using the “Common Cancel” feature code which will either be *9 or 720 depending on the numbering plan assigned to your system.



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