I know this sounds crazy but here's what we're attempting to do:

Our Cisco network is used for both our computing requirements and our VOIP
telephony. The equipment does some kind of clever interrogation of
equipment connected to it at power on to determine if it is a PC or VOIP
phone and reacts accordingly.

However, this is causing any attempt to use PXE to fail miserably. Our
network guys tell me that it would be far easier and quicker to configure
the DHCP service on the switches to give out the neccessary information to
the PCs for the PDHCP service, rather than reconfigure the whole system in
an attempt to fix the problem.

So the question is can this be done?

The network guys have already set the switches to give out dinic.sys as
the bootfile and I believe the IP address of our TFTP server also, but
what is the Preboot Server Transaction server known as?

Am I correct in assuming that once these values have been received by the
PXE client it will just get on with it?