Even 2400 Bauds (= symbol rate rather than bit rate) might be difficult to achieve over a normal phone line. The reason is simple, there are only two wires and both ends try to use the same tone spectrum simultaneously. When you go faster than 1200 Bauds, the modulation scheme changes from FSK to phase methods and the signals become quite difficult to keep apart. This is why in the 'old days' the preferred speed was 1200 in one direction and 75 in the other, they could squeeze two FSK channels in the available bandwidth.
Start by getting a reliable 'OK' back when you send 'AT' - from then on it gets easier. The speed may be programmable using one of the 'S' registers (ATSx=y) but as I said, you may have problems connecting modem to modem at higher speeds. If you do get it working there is usually a command "ATW" that writes the settings into NV memory so they become the default but some modems allow more than one configuration to be stored so you might have an extra digit after the "W" to tell it which configuration slot to use.
Brian.
No that's wrong AT syntax and useless. Register commands are setting a specific register value. However, there's no standard register to set remote speed. You'll refer to the modem documentation. Often, there are AT&G or AT&H commands to set protocol and speed. What's the modem brand and type?ATS=1200
No that's wrong AT syntax and useless. Register commands are setting a specific register value. However, there's no standard register to set remote speed. You'll refer to the modem documentation. Often, there are AT&G or AT&H commands to set protocol and speed. What's the modem brand and type?
According to the modem doc, everything can be set with AT+MS command. The command is in fact common to many 56k modems, e.g. the Elsa/Devolo modems I have been using in older days.
You should really read the documentation and understand what's appropriate according to the application and peer capabilities. Particularly I don't understand why you want to limit the remote data rate. I would expect that default settings cause the modem to negotiate a suitable protocol. Flow control prevents the peer from sending more data than you can receive at the local data rate.
Anyway, if you want a legacy protocol without automatic rate negotiation, you can try AT+MS=V22 or AT+MS=B212.
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