IMAGINE the embarrassment. Your pager has been overtaken by the old-fashioned telephone. Well, only if you've been remiss enough to keep using an ancient - that is, more than two years old - one. Because since the telephone numbers expanded to eight digits, you may not be able to tell who has messaged you - or even what sex they are. Pagers of more than about two years old have only 10 spaces on their display for figures. Fill eight of them with the new numbers carrying a '2' at the front, and the other two are not enough to give you a code for the person's sex and surname, says Hong Kong Radio Paging Association vice-chairman Alex Cheung. 'With two digits for the surname and one for the sex, that means you need 11 spaces,' he said. 'Most of the older pagers have 10, so they can't display in one section.' Of course, you can press the button to get the second section, or page, carrying the fallen-off part of the message - unless your technology is so ancient that you don't have the second page. Then, horror of horrors, you may have to call your pager company to receive the rest of the message. Hutchison Paging said it had instigated a trade-in programme for 10-digit pagers because of this problem. And Chevalier Paging, which sells pagers with 12 or more digits, said it had changed its code system for the caller's sex from three digits to one symbol.