Protocol application Invalid in cisco 7940 IP phone

[aress1234]

I am getting Protocol application Invalid in cisco 7940 IP phone . I am unable to enter the setting configuration by pressing the setting button.

When I power on the Cisco phone it immediately gives the error and I am not able to do any setting . I am also not able to telnet to Cisco 7940 Ip Phone. When I use telnet (IP address of Cisco 7940 IP phone)it gives error message "Could not open a connection to host: Connect failed".

[gajolly]

there r lot of bugs associated with this message so might need to check out the latest phone release avaialble for an upgrade.

[joselo]

Hello:

I had the same error.

My solution:

1.-Reset IP phone to factory defaults press the # key and hold ,then plugging in the CAT6 cable. When factory reset detected is displayed press 123456789*0# and choose NO to save network settings.

2.-Use a DHCP server Router in my case.

ip dhcp excluded-address 192.168.10.1 192.168.10.5

!

ip dhcp pool XYZ

network 192.168.10.0 255.255.255.248

default-router 192.168.10.1

option 150 ip 192.168.10.2 ….Callmanager

lease 10

3.-you can work with ip phone

ip phone : 192.168.10.6/29

Regards

JOSELITO