With the RP-6 or for that mater the XP-8, lets say I want to have just one controler central in an office, controling some plasmas and projectors in meeting rooms close by.
I need serial out to the equipment I am controling, but as I understand it the Serial cable from RTI should not be extened much.

how would you go about extending it with out signal loss ?

You can use the adapters from this website or similar ones and do another cable (male to female) to extend the RTI one.

http://www.easyadapters.com/

You can use cat5 for this. But be aware that RS232 works up to a certain distance. Someone with more experience must help here what do to for long distances. I think there are adapters to convert it to ethernet but easn't this exactly what we are dong above? Maybe some active ethernet solutions?

I think it gets converted to another standard, RS422? for greater lengths.

Are you referring to RS-485, kinda like the balance version of RS-232...

We have had good control with up to 50' before using 22 guage... I usually like to keep this much shorter though.

I have serial extention cables that are over 150 feet that have never had any problems, The serial comunication that we are using with RTI is not very complex, so the chance of errors is rather slim even with long cable runs. I to have switched to using the easy adapters Cat 5 setup which is the best way to go.