The Transport Stream Dock PCB takes advantage of the secondary Transport Stream port on the DTX1's main board, and buffers it to protect the FPGA from static etc. as well as cleaning up any noisy signals using Schmitt triggers.
The circuit diagram can be found here:and an addendum to the user guide for latest firmware supporting this board here Important! Firmware Version 01.00.05, 28th Jan 2016. This version includes support for the TS DOCK PCB and features a new 'Preset 3' optimised for BATC RBTV. When loaded, it will keep your existing presets, but NOT load up Preset 3 and other defaults automatically. If you wish to add Preset 3 contents, you have to re-load ALL presets. This will trash your existing presets so if you want to re-use them you need to make note of them before defaulting the unit. To default the unit, remove power and press the UP and DOWN menu buttons simultaneously whilst restoring power. Keep them pressed until the unit boots. If in doubt email firstname.lastname@example.org. The firmware and upload utility can be found here