Yealink Phone

To restart your phone simly unplug the network cable or if you phone has a power supply then take the power cable out and it will be restarted.

To find the mac address of your phone it should be at the back starting with 0

If you want to check IP address 

his article provides steps on how to get your Yealink phone's IP Address. The steps are for the following Yealink phone models: T21P, T42S, T46S, W52P T41s and W56P.
 

Phone Mode

Instructions for getting the IP Address

Yealink T21P
Yealink T42S

Press OK on the phone. The IP address should be shown on the first line labeled IPv4.

Yealink T46S

1. Press the Menu icon then select Status.
2. The IP address should be shown on the first line labeled IPv4.

Yealink W52P
Yealink W56P

1. Pickup one of the handsets that is registered to the base station, then press OK
2. Press OK on the (i) icon.
3. Press OK on the BASE option.
4.. The IP address of the Base will be displayed on the screen.

If your phone is showing busy

Do Not Disturb (DND) is a feature which prevents your phone from ringing and lets you send all incoming calls directly to your voicemail. DND applies to all lines on your phone.

Follow the steps below to configure DND in Yealink T42s and T46s deskphones:

1. Press the DND softkey button. If this is not an immediately visible, press the More softkey to see additional options
2. The DND icon will show a red indicator when enabled. Press the DND softkey again to disable it

NOTE: All calls you receive while DND is enabled are logged in your Recent Calls list.