October 17, 2018

Round, round we go...

U.S. Robotics

For instructions on how to physically connect it and for general configuration instructions, see the documentation that came with the modem.

Set the DIP switches on the modem to match the settings listed in the table below.

U.S. Robotics External Modem Switch Settings Switch Setting Function 

  1. OFF (Up) DTR (Data Terminal Ready) override
  2. OFF (Up) Result codes
  3. ON (Down) Result codes
  4. OFF (Up) Keyboard command echo
  5. ON (Down) Auto answer
  6. OFF (Up) CD (Carrier Detect) override
  7. ON (Down) Power-on and ATZ reset factory defaults
  8. ON (Down) AT command recognition


Initialization Strings:

When using a US Robotics modem, I have found the best initialization strings are:

Using Caller ID AT&F1&N6S0=2#CID=1
Without Caller ID AT&F1&N6S0=1
Error Correction Disabled* AT&F1&M0&K0&N6S0=1
If you need to connect to older systems using TN1648 boards (2400 baud) you need to turn off error control (ARQ) by adding &M0 to the string like: AT&F1&N6&M0&K0S0=1


Tips and Tricks

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