Talking security token

At a conference display I came across a talking security token. Security tokens are usually key fob size devices which display a number to provide access to a computer system. This creates a problem for people with poor (or no) eyesight. To overcome this, there are devices which look like desktop calculators, with large buttons and display. Some also have synthetic voice to read out the numbers. For security reasons, there is also a headphone socket. The particualr unit I was looking at was a VASCO Digipass 300 Comfort Voice (DP300 CV), but I assume other providers have similar products. There are some security tokens offered on-line, as well as books about them.