MY cisco 7905 model says ethernet-switching disconnected when i pick up the call

SOURCE: 7940 cisco ip phone being powered by a power brick

Change out your cable from the wall drop to the phone. A Cisco phone is capable of receiving inline power (Power Over Ethernet) via the blue and brown pairs of the cable. It sounds like you may have a cable with a short in either the brown or blue, or both pairs, shorting out the power when it is connected via ethernet.

If you can, have your IT Tech check the cable, and the line through the wall to the switch.

SOURCE: my cisco ip phone 7905

Hi,

the reason for this would be that it is not getting it's config from the CallManager (or CME router).

The steps in a phone booting up something like this:
1) DHCP for IP Address, and Option 150 for TFTP Server
2) TFTP to address provided by DHCP Option 150
3) Get config file, a(an upgrade of firmware may occur at this point)
4) Connect to Call Manager/CME as specified in config file

First check DHCP server to see if it is allocating an address to the MAC address of the phone
Second confirm if DHCP is providing Option 150 and that is the IP Address of the TFTP Server (typically one of your Call Managers)
Third check that the phone is correctly configured on CCM/CME. A common error at this stage is that the phone is configured with the wrong model type.

Call back if you get to that stage and are still having problems.

Cheers, Simmo99.