Some Examples of Basic Modem Init Diagnostic Procedure

Assuming you do NOT have the specific manual for the modem.
  1. From Terminal or HyperTerminal, type "ati3" (no quotes), then Return. Does the response say "Rockwell"? If so is it Modem+ or Modem? In both cases, you need to download a copy of the latest RPI Drivers from the the
    Rockwell Web Site.

    Here are some init strings that have been found to work with these Rockwell based modems:

    Modem+: at&f&c1&d2&k3s0=0s7=90+h11
    Modem: at&f&c1&d2&k3s95=1+h3

  2. If the modem is NOT a Rockwell based modem:
    Type at&k3, if the answer is "ok", use the string: at&f&c1&d2&k3
    If the answer is "error", type at\q3, if "ok", use: at&f&c1&d2\q3

    Keep eliminating until you determine which "at" command is in error for your specific modem and leave it out of the string you are experimenting with.

  3. Use at&f (or USR, at&f1) alone to see if they'll work. (Factory defaults SHOULD work for TCP/IP in most cases).

  4. If you have poor telephone line conditions, you may be able to improve connections by disabling modem compression.
    Try at&f%c0 or for US Robotics, at&f1&k0

  5. Dropped connections can sometimes be reduced, (or eliminated), by adding the following commands to the modem initialization string: S10=50 S25=10 S38=5 These settings tend to make the connection more tolerant of breaks in the DTR or telephone circuits.

Note:All modem commands are preceeded by the charcters "at" (no quotes) and are not usually case sensitive.. (I just tend to keep them all the same, either upper or lower is OK).

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