SAE J1850 PWM (pulse-width modulation — 41.6 kbit/s, standard of the Ford Motor Company)
- pin 2: Bus+
- pin 10: Bus–
- High voltage is +5 V
- Message length is restricted to 12 bytes, including CRC
- Employs a multi-master arbitration scheme called 'Carrier Sense Multiple Access with Non-Destructive Arbitration' (CSMA/NDA)
SAE J1850 VPW (variable pulse width — 10.4 kbit/s, standard of General Motors)
- pin 2: Bus+
- Bus idles low
- High voltage is +7 V
- Decision point is +3.5 V
- Message length is restricted to 12 bytes, including CRC
- Employs CSMA/NDA
RS-232 to J1850 PWM cable by ScanTool.net
RS-232 to J1850 VPW cable
See also PC RS232 interface details.