To answer my own question .......there is the option to enable RS-232 (serial) - has anyone had a play to see if we can use the serial port on these cameras over the Ethernet ?
I managed to get a spare 5 minutes to have a play and although I didn't have a USB to TTL (3.3v) converter handy, I hooked up a multimeter to one of the three spare pads on the TOP-201 and ground. I had a nice steady 3.3v
I then had a play with the PTZ on the CMS software - nothing. Tried reconfiguring the serial port to use Transparent / General / Nothing - still nothing.
I logged in through Telnet and had a look at /dev for any interesting TTY ports - there was one labelled ttyS000 so I did a dump of a file through to that - the meter went wild which indicates that we can possibly directly talk to the ttyS000 port on the module.
This opens up all kinds of possibilities for me now - I can hook up a small PIC microcontroller to decode what is coming through the serial port of the TOP-201, control things like a PTZ mechanism, turn on and off lights etc etc. I'd need to write some kind of program to Telnet into the unit and echo commands to the serial port but this shouldn't be too taxing
I've also got a couple of other IP cameras with the same serial outputs on so worth having a further play with