 The numbers on other half of the strap encode the text 'If You [ASCII-24] See', which, given that ASCII-24 is the 'Cancel' character or just 'CAN', makes the complete message 'Listen To The Light If You Can See'.The earlier models were the Datalink 50, Datalink 70, Datalink 150 and Datalink 150s, where the "s" was for small and it was intended to be a lady's watch.The 150 and 150s models are essentially the same, except that the 150s, having a smaller display, has different display addresses from the 150, and thus it needs its own programming code.