Serial Port Pins / Looking into/at the back of the PCjr˙
 
  === == == == == == == == == == == == == == == == == == == == == == == == ==
 ||   ----     ----     ----     ----     ----     ----     ----     ----   ||
 ||  | A1 |   | A2 |   | A3 |   | A4 |   | A5 |   | A6 |   | A7 |   | A8 |  ||
 ||   ----     ----     ----     ----     ----     ----     ----     ----   ||
 ||                                                                         ||
 ||   ----     ----     ----     ----     ----     ----     ----     ----   ||
 ||  | B1 |   | B2 |   | B3 |   | B4 |   | B5 |   | B6 |   | B7 |   | B8 |  ||
 ||   ----     ----     ----     ----     ----     ----     ----     ----   ||
  === == == == == == == == == == == == == == == == == == == == == == == == ==
                           (16 Pin - AMP Connector)˙
 
 
 A1 - pin not used                   B1 - shield/chassis ground
 
 A2 - data terminal ready            B2 - signal ground
 
 A3 - request to send                B3 - signal ground
 
 A4 - transmit data                  B4 - signal ground
 
 A5 - carrier detect                 B5 - signal ground
 
 A6 - data set ready                 B6 - signal ground
 
 A7 - clear to send                  B7 - signal ground
 
 A8 - receive data                   B8 - signal ground