The OEL TTX2000 Issue 2.3 ROM
The OEL Issue 2.3 ROM is an earlier version of the firmware.
It uses the same teletext acquisition code, but a different telesoftware downloader.
The Volex TTX2000 S Issue 1.2 ROM
The Volex Issue 1.2 ROM is identical to the 4Data ROM apart from the data defining the menu screen.