What is TTS?
TTS stands for Twin Track Sound. This means that the decoder comes equipped with two sound channels which allows simultaneous play of full locomotive exhaust sounds (chuff, engine revs etc.) as well as individual sounds e.g. whistles, horns, brakes, wheel slip etc.
What can TTS do?
TTS decoders allow basic reprogramming options, including: short and long addresses, acceleration and deceleration, individual sound volume and some others which are all noted in the documentation that is included with each TTS-equipped locomotive.
What can't TTS do?
Sound functions will only work when used on a DCC controlled layout. The locomotive itself can be operated on a DC/analogue layout if you wish but none of the sounds will play.
Since TTS decoders can only play up to two sound files at once, you can only have the running sound and one individual sound playing at once. You would not be able to have the whistle and brake sounds playing at once for example.
Can I fit a TTS decoder to a loco I already own?
In short, yes. Hornby have announced that they will be releasing a range of TTS decoders as standard items, the first batch are due in stock in September 2017. Bear in mind that all TTS decoder will be fitted with an 8-pin plug.
If you want to fit a TTS decoder in to a loco with a 21-pin socket then you will require an adapter which is available from Bachmann.
36-559 DCC 21-pin to 8-pin adaptor/converter. For locos with 21-pin sockets to use an 8-pin decoder
What sounds can I get on a TTS decoder?
The initial range of stand-alone TTS decoders announced includes sounds for:
Hornby are sure to extend this range over time as they have already released many more locomotives with TTS sound pre-fitted that are not included in this initial release.