Transport / trunk / channel naming question

How can i figure out what the Transport/Trunk/Number should be? I have an asterisk box with SIP phones connected to it. There is a SIP trunk to a mitel pbx that provides connection to the PSTN. I can call from asterisk to mitel, from mitel to asterisk, and from asterisk to pstn, so THOSE pieces are working.

when calling from asterisk (1091) to mitel (4035), the cli log shows device SIP/Mitel/4035. when manager originate is attempted, doesn’t like that string (SIP/Mitel/4035). i CAN use that string in a call file, i can also use that string for cli originate.

It is also possible to use “local/4035@mitel-context”, but i think there are issues reported elsewhere with using local (for example, the call seems to be “answered” when passed to the mitel, not when the user at extension 4035 picks up).

What SHOULD the transport/trunk/number string be, since it doesn’t appear to be what appears in cli log.