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The Smart Phone Control Protocol (SPCP)


The Smart Phone Control Protocol, or SPCS, is an addition to the Skinny Call Control Protocol (SCCP) that is only supported on the CP-500, SPA500, and SPA525G and SPA525G2 phones.

(Note CP500 only support SPCP whereas SPA5xx support SPCS or SIP)

79XX phones register with their SCCP call control using a proprietary handshake that consists of a series of messages. During the registration phase a number of things happen:

1. Phone (Station) sends  a Registration Request

2. Request is acknowledged by the Call Control (CME/UC500)

3. Capabilities are advertised

4. Button template, Softkeys, Line Status, Display message, Speed dials Time and date are requested by the phone and sent by CME/UC500

When the phone is a 500 series phone, two additional messages precede all this handshake, namely an SPCP Token Request and an SPCP Token Acknowledgement (if successful) or Token rejection (if unsuccessful). A Token ACK can only be sent by UC500, while an ISR will always send a Token Reject. This prevents the phone from registering to any call control different than UC500.

We have seen a case where if you build a SPA525G phone as a TYPE SPA525G2 phone in the UC500, it will give you an SPCP Token Error when it tries to register.   You would see this on the console port or the Telnet session with 'terminal monitor' enabled.


I don't understand this.

the older 500 series phones, SPA521SG and SPA524SG (now in EoS notice) were supported on both the UC500 and CME.

Cisco now says the replacement product for the SPA521/524 is the Cisco Small Business Pro SPA500 series. This only supports the UC500?

Am I missing something?

David Harper
Cisco Employee

The CP-52x phones were only ever supported on the UC500.  If you saw something documented stating otherwise, then that document was in error.  If it is one of our docs, please post the URL so it can be corrected (though the question is somewhat academic now admittedly).




thnx for the reply!


Hello Dave,

I am studying a solution with 2901 and CME. I was interest in CP-500 phones. When I was reading them data-sheet I found:
"Supported in Cisco Unified Communications Manager Express versions 4.2.6 and above using Smart Phone Control Protocol (SPCP)"
This is the address of this doc:

But when I was gathering information about SPCP, I found this post.

So CP-500 are only compatible with UC-500? Can you please help me to understand?

Thank you a lot.
Best regards Antonello.

David Harper
Cisco Employee

While that document is technically correct when it says support in CME with the SPCP protocol, it is misleading by not making it clear that CME only support SPCP on the UC500 platform.  I will get that corrected.

To reiterate, the CP-500 phones, and the SPA500 phones for that matter, with only operate with CME running on a UC500 - not any other platform.




Hi Dave,

thank you really much!

Well I don't like so much this policy, but is good to know.
Now I have discoved this policy, 2 questions have came to my mind:
1. SPA 500 support SIP, with SIP I can use them with legacy CME?
2. I can use a special switch with UC500 series, or I can use any cisco switch?

Thank you really much.
Best regads Antonello.

Marcos Hernandez


Here are the answers:

1. They support SIP and you will be able to make them work with CME, but TAC does not support this deployment,

2. The recommended switch for CCA compatibility is the ESW500 series.


David Harper
Cisco Employee

Just to expand on Marcos's answer a bit - you can use other switches with the UC500, but the ESW500 switches are the best choice since they generally require much less in the way of configuration and setup time.  The default configuration of the ESW500 switches was developed specifically with the UC500 in mind, and in most cases all that is really necessary is to plug the switch in.

Other switches will generally need at least some configuration to match the VLAN numbers in use on the UC500, and non-cisco switches will generally require some fiddly configuration applied to the switch ports to allow them to support IP phones.




Thank you really much both of you.



Thank you for this very informative thread. I have been searching everywhere for such information. I even used Google to search for this info without luck (may be something that I am doing wrong).

Now I have a question please. Is there any benefit or disadvantage to using SIP for the SPA5xx phones over SPCP with a UC5xx? Meaning, is there a downside to using SIP? What protocol should I be using for the SPA and UC signaling? Is there any loss of features using the other protocol?

Lastly, is there a configuration guide for this?