Wow, You learn something every day. Apparently at one time DCS would let you transmit an ASCII ID too. Kenwood made a box called CD-10 that would plug into a regular radio to display callsigns received in this way. CD-10 Manual
Looking around I see reference to an HT made in the mid-80s that transmits the IDs. Kenwood TR2600A Very neat stuff. Apparently it sounds like MDC which is a system that is or was used in commercial radios used in police cars to transmit a station ID at the beginning of every transmission.
This is the kind of stuff that is only just recently available again and even then only if you use Dstar. It'd be pretty awesome if the DCS ID thing came back on the analog side I think.
Edit: Kenwood's TM211 had support for transmitting the IDs. Via the TM211 manual (Section 5) I see that it assigned letters and numbers to various DCS numbers.