“b) Change the firmware in your phone from SCCP to SIP. For many people, this is easier to get set up, since it doesn’t have an many features or options. You can get a solid 90% of what the phone can do and not have to install any new channel drivers.”
By “this is easier to get set up” going from SCCP to SIP on 7975G. Did you mean the below instructions?
ARTICLE : Configuring Cisco 7975 IP Phones for SIP
Anyone who has had the “pleasure” of trying to configure a Cisco 7975
phone with a SIP IP PBX system such as Asterisk, trixbox, or 3CX can
attest to the fact that the phones are very picky with their config
files and much of the information that is really handy to know is simply
not documented anywhere. On top of that, to get the phones to even work
right you have to use very specific versions of the SIP firmware as the
phones are not designed to work with third-party phone systems that
talk generic SIP messages. While I can tell you that Cisco recommends
using SIP firmware 8.3.2 SR1S, I cannot provide the firmware files
because of their licensing agreements. Assuming you can get the correct
firmware copied to your tftp server, and your DHCP server is serving out
Option 66 to tell the phones where to look for its config files (yes,
these are mandatory requirements), then we can get into how to actually
configure the phones themselves.
To start off with I have created a set of files that will help you get started, you can download the set here (download).
Inside the zip file are the following files:
SEP7975.cnf.xml – A clean example fileSEP0023331BEA0A.cnf.xml – Same as the previous but showing how the mac address is added to the fileDesktops\320x216x16\7975Logo.png – Background image for phoneDesktops\320x216x16\7975Logo-TN.png – Thumbnail imageDesktops\320x216x16\List.XML – Background image config file
Let’s assume your phone’s mac address is 0023331BEA0A, we will need a
file named SEP0023331BEA0A.cnf.xml for the phone to configure itself.
Using the included files as a guide, we need to edit the following
lines:
Line 27: 192.168.5.49
Change IP address to IP address of your PBX system. Using a host name tends to cause the phone to not parse the file properly.
Line 71: http://{TBexternalIPaddress}/xmlservices/authentication.php
Line 72: http://{TBexternalIPaddress}/xmlservices/PhoneDirectory.php
Line 75: http://{TBexternalIPaddress}/xmlservices/index.php
Line 78: http://{TBexternalIPaddress}/xmlservices/index.php
If you are using XML services you will need to change the above lines to the correct URLs.
Line 155: VoipStore
Now I know you don’t want to change this
Line 160: 402
Line 162: displayName>402
This is the text shown next to the line key, usually the extension number
Line 161: 001FCA368894
Line 163: 001FCA368894
Line 170: 001FCA368894
Lines 161, 163, and 170 are the SIP login, on some systems this is
the extension (trixbox CE, 3CX, FreePBX) and on others it is the mac
address (trixbox Pro).
Line 164: 192.168.5.49
The proxy IP address is the IP address of your IP PBX system.
Line 171: 9svHcd92t4H
The auth password is the SIP password (secret on some systems) for this extension
Line 174: 8555
This value is the number to dial to access the voicemail system. On
trixbox Pro this is 8555, on trixbox CE it is *97, for 3CX this is 999.
Lines 184 – 209 repeat the same information to add another active
line key, you can continue adding sections like this for all eight line
keys.
Adding the background image
If you copy the existing files from the zip file to the right
locations, you should be able to activate a new background image for
your phone. Press the Settings key, then 1 for User Preferences, then 2
for Background images, use the directional keypad to move to the image
you want to use, then press the Select softkey, then press the Save
softkey. Your new background image will now display in all its glory.
Troubleshooting
I cannot begin to stress how picky these phones are with their
configuration files. If you are making changes and rebooting the phone
and your changes do not seem to be taking effect, go to Settings,
Status, Status Messages to get a list of errors that the phone is
encountering. Typical ones to ignore are the following:
Error updating LocalNo CTL installedFile not found: CTLFile.tlv
Those are actually “normal”, what you do not want to see is “Unable
to Parse file”, that will tell you that it did not like something in
your config file. This can be something like using a host name when it
wants an IP address. Just understand that you will probably experience
quite a bit of frustration getting the 7975 to work properly, but with
enough persistence it actually is possible.