I have been using serial port to handle modem communication for quite some time in some production environments. Everything was great so far. Recently I heard something about synchronous/asynchronous communication modes. I think I have been using asynchronous mode all this time. Now I have a requirement to use synchronous since some clients will use the same. I read about the basic theory on this - what are the differences and other stuff - but I'm not sure if I can accomplish this with the modem(s) I already have. I tried to search several online shops but I cannot find the "synchronous" or "asynchronous" terms in any modems' specifications. I also found a couple of articles with some AT commands that can switch a modem to synchronous mode. I tried that but they do not seem to have any effect on my modems. Actually my modems manuals do not have any reference to such issue. The questions:
- Are there special modems for synchronous communication?
- If so, can you recommend me one?
- If not, are there any AT commands or other settings that will switch my existing hardware/software to use synchronous communication mode?