Handset Checks

No Dial Tone? / No Power? / Requesting DHCP

  • Check the cable from the handset to the floor/wall port is connected, from the patch panel to the switch / router is also connected.

  • Plug the handset into a working port or directly into the router (connect a power supply as no POE from router) to check if the fault follows the phone. If so, the handset may be at fault. If it does not it could be a cabling issue.

  • Regarding DHCP, also confirm that your DHCP server is running and working, you could do this by connecting a computer/laptop onto the same circuit and confirm whether you are able to obtain an IP address.

Unable to receive calls, but can make outbound calls

The handset may be in DND (Do Not Disturb mode).

  • DND uses a feature code that is implemented via the handset by either pressing DND / mute button (depending on handset) or physically typing the following codes:






DND Toggle


DND Enable


DND Disable

Call Quality

Things to consider:

  • Which calls are affected, internal / external

  • Which users – specify ext numbers / user names

  • Issue reported? Crackling, audio loss, echoing etc


This is likely down to a local network issue. Cabling, switch, electrical interference. Check cabling to rule out a local fault and if possible confirm whether the fault is still present when a handset is connected directly to the router with a single ethernet cable avoiding switches and other structured cabling.


Check cabling, from the handset to floor port, then to the switch, then to the router etc – echoing is typically caused by electrical interference – rule out a local fault before logging on the Helpdesk. Also confirm that echo is no longer present when not using speaker phone, and using the handset receiver instead.

Audio loss

  • One way audio, audio dropping out?

  • Internal or external call?

  • Which users are affected? Are all users on the same network?

  • Are all calls affected or is the issue intermittent?

  • Certain Telephone numbers affected?

  • Description of fault reported? i.e – call dropped unexpectedly, gaps in audio on one side of call etc.

Examples are required for further investigation. Format of examples:

Timestamp of Call

Number/User Ext From

Number/User Ext To


Description of Issue

Timestamp of Call

Number/User Ext From

Number/User Ext To


Description of Issue

Not Registered / BLF State Frozen

Reboot the handset

Snom- Press the following key combination on the dialpad **##.

Other- Remove the ethernet cable from the network port on the back of the handset for around 10 seconds and put it back in - *If powered with PSU remove this and place back in again also*

No Failover between POPs

  1. Ensure firmware is up to date

  2. If device is supported, confirm it has been recently auto-provisioned

  3. If device is unsupported

    1. Ensure registration expiry is set to 600 seconds (10 minutes)

    2. Ensure the Proxy is set to reg1.byphone.co.uk (and not a static IP address)

  4. If the device has an uptime greater than 30 days, a reboot may be required to clear any DNS cache

  5. Ensure router is not caching DNS longer than the specified TTL of 600 seconds (your IT support may be required to confirm this)

  6. Ensure the local network is not restricting access to IP ranges other than our

  • Primary POP Registrar IP

  • Secondary POP Registrar IP

  • Tertiary POP Registrar IP