Delphi 2005 to C++ dll interface

I would like an interface that will allow my Delphi 2005 point of sale software to talk to a Chinese C++ dll in order to obtain the caller id..
The documentation can be found here - http://tel-rec.tech/TelRecDoc/English/
The caller id is returned by the ChannelStatusChanged heartbeat (Login -> Heartbeat in the documentation).