| ??? 06/03/09 05:16 Read: times |
#165776 - Practical RS232 (may not be the Pro way ) |
OK there are hundreds of places on the net / this forum where one can get info. on the DTE,DCE,9pinMale, 9PinFemale,25pinmale, null modem..etc And that IS the problem.
I had to remotely guide a technician on fixing a broken RS232 cable and I went this way ( and it worked !): 1. Measure the voltage on pin 3 with ref. to pin 5 of the 9 pin male connector on PC. It read -9.1V and so its the TXD pin. 2. Now on the MCU board measure the voltage on the two leads from the MAX232 leading to the female 9pin connector. That which reads around -8V or so, is the TXD of the MCU and that should be connected to the pin 2 of the connector. Over. Just as a cross check, after the link is made read the voltages on pin 2 and 3 with ref. to pin 5 . Both should read negative as above. Are there any pitfalls in the above method ?? raghu |
| Topic | Author | Date |
| Practical RS232 (may not be the Pro way ) | 01/01/70 00:00 | |
| I have used this method for many years - no pitfall | 01/01/70 00:00 | |
| Are there any pitfalls in the above method ?? | 01/01/70 00:00 | |
| only with resistors and leds | 01/01/70 00:00 | |
| True | 01/01/70 00:00 | |
Thanks | 01/01/70 00:00 |