Inc. It was initially released for $149 around May 1980 as the successor to Newdos 2.1, it was another alternative to the notoriously fickle (and unreliable) TRSDOS which was shipped by Radio Shack, NEWDOS/80 offered a more versatile and user friendly ...
Word length = 8 Bits, Stop Bit = 1, No Parity Bit, sets DTR and RTS to logical “TRUE”. Now by connecting a MODEM to the RS-232 Serial port you have a pathway for data to and from the Telephone.