Init Strings

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What is an init string?

Different modems can't necessarily talk to each other as set right out of the box.  Modems use many different settings and protocols.  In order for two modems to communicate, they must agree on many things such as speed, error correction, compression algorithms, etc...  By sending a modem an init string, you can control some of these parameters.


What do I need to put in my init string?

In general, the modems used by paging carriers run at a speed from 300 to 2400 baud (1200 being the most common).  They don't typically use any form of error correction or data compression protocols.  In many cases, if your modem tries to use either of these protocols, your modem will be unable to communicate with the paging terminal's modem.  In your init string you should include settings to lock you modem's baud rate to that of your carrier's modem, disable error correction protocols, and disable data compression protocols.  In addition NotePager Pro would like your modem to issue English response codes (rather than numeric response codes), and issue complete connection information.


Do all modems use the same init string?

No, many different modem manufacturers use their own set of modem commands.  Init strings may even be different between models by the same manufacturer.


My init string works on one carrier but not the other.

You may need a different init string to connect to each carrier.  In general your init strings will be the same, but not always.


What init string should I use?

There is no easy answer to this.  In general, if your modem is a 2400 baud model or slower (very old models) you won't need an init string.  These older modems sometimes work best when communicating with the paging terminals.  Anything faster (9600, 14.4, 28.8, 33.6, 56K, etc.), will probably require an init string.  Some of the most common init strings are listed below.  If you have a less well known brand modem, you may need to use the documentation include with you modem to create an init string.


Common Init Strings


AT&FQ0V1X4&D2   - Minimal settings.  Works with most 1200 and 2400 baud modems. Some modems use &F0 rather than &F.  All '0' are zeros not oh's.


AT&FQ0V1X4&D2N0S37=5   - Hard coded baud rate.  Works with many 14.4 and 28.8 modems.  The added codes locks the connection baud rate to 1200 baud.  Use S37=3 for a 300 baud connection, and S37=6 for a 2400 baud connection.  Some modems use &F0 rather than &F.  All '0' are zeros not oh's.


AT&FQ0V1X4&D2N0S37=5\N0%C0   - No compression/error correction.  Works with many 14.4, 28.8 and 33.6 modems.  The added codes turn off data compression and error correction.  You can try using only one of the two additional codes (\N0 or %C0) if you modem rejects using both.  Use S37=3 for a 300 baud connection, and S37=6 for a 2400 baud connection.  Some modems use &F0 rather than &F.  All '0' are zeros not oh's.


AT&F0Q0V1X4&D2&B1&K0&M0&N2   - US Robotics (3Com) string.  Works with most US Robotics/3Com 33.6 and 56K modems (and some others too).  Use &N1 (instead of &N2) for a 300 baud connection, or &N3 for a 2400 baud connection.


AT&FQ0V1X4&D2N0+MS=B103  - This string has been found to work with some of the newer winmodems.  Set the baud rate to 300 when using this string.


Note: all '0' characters in the init strings are zeros not oh's


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