These were originally built for AT&T and can be found from several sources (e.g. EarthLCD). Please note, however, that the original AT&T firmware must be replaced in order to use these displays in your project and depending on where you get your panel, the firmware may or may not have already been replaced.
The interface is RS-232 format with regard to timing (19,200 baud, 8 bits, no parity, 1 stop bit) but the Rx and Tx signals are TTL level, positive logic. The panel requires +5V at about 70mA for the main logic and a negative voltage for the contrast control, -9 to -12 volts at about 2mA. This is often supplied by a MAX232 chip if you don't already have a suitable negative supply in your design.
This display can be driven directly from the TX line of a esp32.