Nick ->

to the board, if you could please fill out your profile completely.
If I understand you right your trying to dial directly to the conf. room single line phone.
We will need a few bits of info to help you figure this out;
What type of Toshiba system do you have?
What number are you dialing within the company to call this phone?
Where are you trying to change the station type?
Do you have DID's on a PRI circuit on your system?
In sticking my neck out I'd say you have a CTX and a PRI with DID's.
You won't be able to change the type but in DID programming you can find which DID, if any is assigned to this single line and if one isn't then if ones available to assign it.