If Talisman is anything like Argus 2, the 'BST control' RS232 is likely to be a separate entity to the 'camera control' RS232. I am not aware of any ISG 'camera' control software in public.
The 'BST' one for the later Raytheon core (205D) is public. Which PCB you have will depend on the date of your camera.
Does the BST control PCB have a multiturn pot on it and edge connector as Frasers' images ?
If so that is the 'old' (200A) PCB, and while I am sure it probably also had RS232, that was only for Raytheon use, not customers.
The 'new' 205D PCB has no pot and a connector at both ends with RS232 on it for the software that is 'out there'. I can look out the pinout later this week on an Argus camera.
I'd suspect the 200A pinout was the same though, so may be worth trying.
Bill