The TCB is compatible with Tamiya and Taigen/Asiatam type mechanical recoil units. However some wiring changes may be necessary.
Tamiya Recoil Units
Tamiya recoil units are plug-and-play, except you need an adapter because Tamiya uses a non-standard plug. See the Accessories page for more information on Tamiya adapters.
Taigen/Asiatam Recoil Units
The TCB is compatible with Taigen/Asiatam mechanical recoil units, but they must be re-wired. This requires some very simple soldering. You can still use the same 3-pin plug that comes with the recoil unit, so no extra parts are required. After the modification is done, the unit plugs into the RECOIL port on the TCB.
For correct operation, make sure you select Mechanical Recoil as the Mechanical Barrel type on the Motors tab of OP Config (as opposed to the other option which is Airsoft).
See the video and photos below for instructions on how to modify the recoil unit.