The answer to your first question is no. Starting with the 2001 models (I think) Volvo did away with the need to enter security codes.
The short answer is: When active, TP allows the radio to override whatever you were listening to in order to allow radio stations to broadcast emergency information. It is part of the RDS or RBDS, that allows the radio stations to broadcast extra information such as call letters, program type (talk radio, pop, etc) as well as other things. It would only function if you are in an area using RDS and only in emergencies, I believe.
BTW, I did find TP info in the owners manual. It is available online. Here is a link for the '06 V70