Thanks for the reply Richard.

So am I reading it right that when the led's have lit up, they are in the 'ready' condition to receive another run of data?

Problem I'm having is when I run the next run of bytes to change colour nothing happens.

Bearing in mind what you've said I'll have a play tonight a let you know how I get on.

Just to add, when the data stream stops for >=50us the Data_Pin must be in the pin LOW condition?

Thanks again: David