Can i use a sip phone and a sccp phone on the same Asterisk server. Can these two devices communicate each other? 
Yes. Yes. (Although Asterisk will need to be a client for at least one of them.
Yes SIP peers can talk to SCCP peers just like they can talk to IAX peers.
I have tried the SIP calling SCCP with Cisco phones.
Ok, Thanks for your answers.
I want to connect my sccp phones on an asterisk server and i want to create a sip trunk with 3CX PBX. In this case the sccp phones from Asterisk and sip phones from 3CX will communicate each other? 8)
The discussion concludes that SCCP & SIP modules can run in parallel on Asterisk to support both SCCP & SIP devices. The same can also be done using Skinny but that has limited feature support for SCCP devices. To gain full access and class features - one should have sccp installed on the node. Please correct my statement and advise if the case if different. Thanks
captshook: didn’t you forget the payload?
Skinny is the Asterisk implementation of SCCP. The discussion did not consider the limitations of using SCCP (However a lot less work has gone into skinny than SIP and Asterisk generally cannot support direct media across different protocols, even if they both use RTP. Asterisk is basically a back to back user agent, with some optimisation when both parties are using the same protocol).
So… Can i do this or it’s not possible? 
See the first reply. It is normal use of Asterisk.
Ok but i ask for the trunk between 3CX and asterisk. Can i call from a sip phone on 3CX to a sccp phone on Asterisk? Is it possible?
No problem for Asterisk. You will have to ask the 3CX people about their side.