In most situations, the most important part of the modem initialisation string for WintextCom Personal Information Manager(tm) to be able to establish a telephone call is the part that determines the connection speed. The connection speed is called the Baud rate, or bytes per second (BPS), and modems can talk to each other at anything from 300 Baud or even slower up to 57,600 Baud or faster, and usually default to automatically detecting the connection speed. A modem attempts to determine the connection speed to use with another device trying to talk to it over the 'phone by running through its range of supported Baud rates until it is the same as the one at the other end of the line, and if two modems are trying to detect the speed in this way, the chances are that they will never agree and the connection will fail. For Typetalk, it is better to force your modem to connect at 300 Baud. The modem must support CCITT, V21 standard, for this to be possible.

WTC attempts to suggest a modem initialisation string on the basis that the modem uses the "AT+MS" command to set connection speed parameters. This is commonly the case, but not always. There are also other factors which may have a bearing on connectivity in certain situations. The following sections of this installation guide describe a formal procedure that might lead to a correct modem initialisation string if the one suggested by WTC does not produce correct operation, or if WTC cannot suggest one at all.

Page url: http://wtcmanual.wintextware.com/index.html?wmi_connection_speed.htm

Connection Speed