Serial Cable

From MobileRobots Research and Academic Customer Support

What is the correct serial cable to connect a computer to the robot?

Use a "straight-through" DSUB 9-pin RS-232 serial cable. It should not be a "null modem" or "crossover" cable. If your cable is wired this way, you can add a "null modem adapter" to unreverse the connections back to "straight through". You can either use the HOST port on the external control panel, or the HOST port directly on the microcontroller board (see Appendix A of the robot Operations or Technical manual). The robot checks DTR (4) to detect that a computer is available (so the computer must set it). It uses TXD (2), RCV (3) and GND (5) for data communications. It sets DSR when the robot is on and operating, and also sets HRNG (9) as a signal of a low battery condition (which the computer can use to begin shutting down cleanly before the robot shuts down).