Yealink SIP- T28P User Manual

Troubleshooting
141
The web user interface prompts “Firmware of the SIP Phone will be updated. It will
take 5 minutes to complete. Please don't power off!”.
4. Click OK to confirm upgrading.
How to reset the phone?
Reset the phone to factory configurations after you have tried all troubleshooting
suggestions but do not solve the problem. You need to note that all custom settings will
be overwritten after resetting. We recommend asking your system administrator for
advice before resetting the phone.
To reset the phone via phone user interface:
1. Press Menu->Settings->Advanced Settings (default password: admin).
2. Press or to scroll to Reset to Factory, and then press the Enter soft key.
The LCD screen prompts “Reset to factory settings?”.
3. Press the OK soft key.
The LCD screen prompts “Resetting…Please Wait!”.
The LCD screen prompts “Welcome Initializing…Please Wait”.

Yealink SIP- T28P Specifications

General

Expansion module support	Yes
Ethernet LAN (RJ-45) ports	2
Keypad number of keys	48
Voice codecs	G.711, G.722, G.723.1, G.726
Handset type	Wired handset
Product type	IP Phone
Product color	Black
Touchscreen	-
Display resolution	320 x 160 pixels
Lines quantity	- lines
Phonebook capacity	- entries
Number of VoIP accounts	6
Bluetooth	No
Security algorithms	HTTPS, SSL/TLS
AC adapter input voltage	100 - 240 V
AC adapter output voltage	5 V
Power consumption (typical)	2.6 W
Operating relative humidity (H-H)	10 - 95 %
Compliance industry standards	IEEE 802.3af
Number of handles included	1 pc(s)

Weight and Dimensions

Depth	204 mm
Width	273 mm
Height	42 mm
Weight	1050 g