Using Profibus

Hi everybody, I have a question regarding Profibus. Well the thing I work for an OEM and we are changing over from AB to Siemens and well my question is as follows.
Could I modify my program using a modem and could I adjust my drive plus change my Touch Screen from a distance. I was told from are suppliers that yes we could. Because they also said that we could go any direction we wanted to the control panels, but soon fund out that we could only go in series without adding anything else to the system.

So if any body could give me a heads up I would much appreciated, it will save me allot of time when it comes to trouble shoot via modem and not **** off any customers with empty promises.

Thanking you guys in advance for the info.

I assume you are talking about the S7 300/400 PLC's. You have to get the teleservice adapter and teleservice software to Dial into the PLC's from home (or whereever). Another option is Internet/Ethernet. It is difficult to setup if you haven't done it before.

As far as modifying TP's from a distance, you can. Use the MPI download mode and you can plug into any port on the same bus run to download your changes.