Wallet Card at NYC's last cab call sign

In the early twentieth century cab call signs could be seen at every major hotel and entertainment venue, providing an easy way for people to know when their cab had arrived. People would take a number and wait for their number to flash on the sign, meaning that their cab had arrived. Today they are all but extinct, with the last cab call left in the city perched above the marquee of the St. Regis Hotel, with the numbers always displayed as 000.