From the end of the 1990s, Sony put an alternative to a front panel numerical keypad to access tracks : what it calls the "AMS" rotary button. You rotate the button clock-wise or counter-clock wise to sequentially navigate through the CD (or SA-CD) tracks and once you get the track you want, you push the button to launch the player.
This interface is fast and easy to use. At least, it is handy to navigate through NTTY's test CD tracks, especially when CD texts describing the track contents have been programmed and are being showed on the display of the player.