You can simply add a TL1 or TF4 to locos with decoders made by other DCC manufacturers. In the case of some supersonic decoders made by other DCC companies that are not transponding compatible, you will need to turn off the supersonic feature when you want to use transponding. Digitrax supersonic decoders are compatible with transponding and can be used in supersonic mode while transponding.