ShoreTel to Cisco SIP trunk

[pndscm]

I have a SIP trunk built between my Cisco 8.5 system and my ShoreTel 12 system. ShoreTel phones can call Cisco phones with no problem. But when the Cisco phones call the ShoreTel phones, it goes to a Fast Busy. I can see the SIP packets from the Cisco going to the ShoreTel switch but the call never connects. I have read a couple threads saying this is possible. I'm leaning toward a setting in the ShoreTel trunk group being wrong but I have tried about all the Incoming Call settings without success. If someone could give me a shove in the right direction, I'd appreciate it.

 

[whykap]

Have you verified that the Shoretel is not looking for sip authentication credentials? That might be the reason your calls are rejected.
I would agree with you that there is something in the shoretel rejecting the call since they work the other way around.
Unfortunately the only way to debug this on the cisco side, since you are terminating the trunk on the ccm and not a cube is through RTMT which is not real time, so it's very time consuming.
That would be the only way to verify your reason of failure.

Also there is a shoretel forum here on tektips so you might want to seek advice there as well. Shoretel is one of the systems I have not crossed paths with, but heard very good things about.

 

[whykap]

I'm sure you have this already but just in case:

http://support.shoretel.com/products/mobility/downloads/mobility_cisco_integration_guide.pdf

 

[pndscm]

Thanks for the response. I went through the ShoreTel forum then I searched and the thread I saw stating that it can be done was from JacobNunley on the Cisco Forum so I posted here.
I appreciate the link. I did a quick once over but I'm not sure that applies to my situation as it looks to be using a specific piece of ShoreTel gear that I'm not using.