I have an elementary question about serial ports. Perhaps someone here have the answer, as he perhaps knows, how the driver works.
I observed that two modems attached to the DSUB9 (RS232 Serial) behave different. I can speak with the "Elsa Microlink 33.6TQV" with almost any speed (using "cu" command), also similar speeds, in which one is not exact multiple of the other. With the "Sony Ericsson GM29" only with a speed of 9600bps. If I give it the two commands *E2FAX and &F, I can do it with 19200bps, and only with 19200bps. Why? Does the first modem adapt its comunication speed with the computer? And if this is a normal behaviour, why is the second modem so strict with the speed? What are the consequences of this behaviour? I tried to use "efax" program with the GM29, and got always the following error: >> efax: 50:29 opened /dev/cua01 efax: 50:35 sync: dropping DTR efax: 50:35 Error: tcsetattr on fd=3 failed: Invalid argument efax: 50:40 sync: sending escapes efax: 50:46 Error: sync: modem not responding [...] efax: 50:46 done, returning 4 (no response from modem) << I googled, some people had the same problem, but I found no solution. After changing the speed, I did not have this problem anymore (but till now I did not manage to send a fax :). I wonder that "efax" program does not allow to change its speed and that its man page do not mention that the modem must work with exactly 19200bps (or something else). Did somenone manage to send Fax with an UMTS Stick? What vendor and device? And if somene has an UMTS Stick that answers "+FCLASS" to "AT+GCAP", then I would thank for a hint, perhaps per Email, to the its vendor, device and answer to "AT+FCLASS=?". Regards Rodrigo
