I do not have a cisco contract or license, but I did order the Cisco CP-8851 IP Phone from Amazon, and was hoping that I could configure it to work with my VoIP SIP PBX. But I can't seem to log into the Web GUI to configure anything, it seems pretty locked down. When I go to try to download anything from Cisco, it seems that the Cisco site will not let me because I don't have an active contract.

How else could I configure my device to run on my VoIP PBX? I have the Cisco 525G2a and was able to configure it from the Web GUI just fine, but I wanted a nicer phone.

  • i guess by default CP-8851 run SCCP not SIP , so first of all you will need POE switch to power on this phone -> DHCP server to assign it IP -> SFP server to assign this phone its image , regarding the SIP image may you can ask any integrator you know to download this image for you
    – Gadeliow
    Sep 15, 2015 at 13:57
  • What is scc, and can I convert it to run SIP?
    – billsecond
    Sep 15, 2015 at 14:01
  • sorry i just type it wrong
    – Gadeliow
    Sep 15, 2015 at 14:01
  • No, they're SIP only phones. The only thing to "download from cisco" is the running software image, which shouldn't be needed for a new phone. Documentation is freely available.
    – Ricky
    Sep 15, 2015 at 17:32
  • But then how can I configure it? The web interface is read only.
    – billsecond
    Sep 15, 2015 at 18:03

2 Answers 2


here i can gave you the basic steps you need and i'll guide you to how accomplishing this proccess

By default most Cisco VoIP phones come configured for Call Manager, which uses the 'Skinny' protocol - SCCP. most of other PBX has 2 implementations for this channel

• Skinny implements a very basic set of telephone functions and ships with asterisk.
• SCCP has implemented more of the SCCP protocol, so some class 5 features (hold, transfer, forward, etc) should work.

However, cisco phones can be reconfigured to use SIP (recommended for use with other PBX than CUCM):
make sure you have the next

  • DHCP - By far the easiest way to configure the phones IP address is via DHCP, make sure you have a fully working DHCP server before continuing.
  • TFTP Server - The phone picks its firmware and configuration up from a tftp server and you'll therefore need to have one on your LAN for this to work.
  • Download Firmware , i know it is impossible for the normal users but may you can get from any integrator you know or from internet file sharing sites
  • Create The Config Files . please check this link Asterisk it is taking Asterisk as an example for free PBX

I think that I may have figured this out, here are some links:



This is the link that shows examples of how to do it. I will check it out and let you all know. http://www.minded.ca/2009-12-16/configure-cisco-ip-phones-with-asterisk/

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