In addition to being able to change individual settings with AT commands, modems generally have several built-in settings templates, which can be installed in one go with a single AT command.

It is common practice, and very advisable, to begin a modem initialisation string by installing the default template, the one which constitutes the modem's settings when it is first switched on, before any changes are made. This ensures that all current settings of the modem are known, or can be determined if required, before starting to change them to reach a required configuration.

The ubiquitous command for installing the default template is "at&f0". Note, however, that some modems will return an error if 0 is included, whilst modems which have more than one built-in template will assume 0 if no number is specified. For this reason, the default starting point for building the initialisation string in the WTC settings file is "at&f".

To this basic command should be suffixed the remainder of the initialisation string. Bear in mind that sometimes if the modem does not seem to be acknowledging a setting specified in the initialisation string when WTC sends it automatically at startup, it may be because it is being sent too fast and increasing the inter-character delay might fix the problem. Alternatively, some modems will accept data faster if new line and/or pause characters ("!" and "~", respectively) are included in the initialisation string; if you include a new line in the middle of the string, you must repeat "at" before the next command.

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Setting the Modem's Default Template