.--.
/  o-|-- 1 DCD Data carrier detect
|o---|-- 6 DSR Data set ready
|  o-|-- 2 RX  Receive data
|o---|-- 7 RTS Request to send
|  o-|-- 3 TX  Transmit data
|o---|-- 8 CTS Clear to send
|  o-|-- 4 DTR Data terminal ready
|o---|-- 9 R   Ring indicator
\  o-|-- 5 GND Signal groun
 `-+` 
   |
   `---- Protective ground

 .--.
/  o-|--  1 GND  Protective ground
|o---|-- 14 TXD2 Transmit data (2)
|  o-|--  2 TXD  Transmit data 
|o---|-- 15 TCL  Transmitter clock (DCE)
|  o-|--  3 RXD  Receive data
|o---|-- 16 RXD2 Receive data (2)
|  o-|--  4 RTS  Request to send
|o---|-- 17 RCL  Receiver clock
|  o-|--  5 CTS  Clear to send
|o---|-- 18 
|  o-|--  6 DSR  Data set ready
|o---|-- 19 RTS2 Request to send (2)
|  o-|--  7 GND  Signal ground
|o---|-- 20 DTR  Data terminal ready
|  o-|--  8 DCD  Data carrier detect
|o---|-- 21      Signal quality detector
|  o-|--  9      Test pin
|o---|-- 22 RI   Ring indicator
|  o-|-- 10      Test pin
|o---|-- 23      Data signal rate detector
|  o-|-- 11
|o---|-- 24 TCL  Transmitter clock (DTE)
|  o-|-- 12 DCD2 Data carrier detect (2)
|o---|-- 25 
\  o-|-- 13 CTS  Clear to send(2)
 `-+`

  ,--------+
  |     ===| 1 RTS Request to send
  |     ===| 2 DTR Data terminal ready
.-+     ===| 3 TXD Transmit data
|       ===| 4 GND Signal ground
|       ===| 5 GND Signal ground
'-+     ===| 6 RXD Receive data
  |     ===| 7 DSR Data set ready
  |     ===| 8 CTS Clear to send
  '--------+