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Method for Dynamically Determining Which Modem Is Installed

IP.com Disclosure Number: IPCOM000062579D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Grafe, RJ: AUTHOR [+4]

Abstract

A method is described for dynamically determining the type of modem installed on a Personal Computer when two are supported, thereby determining the correct command table for use by autodial, without prompting the user for information. When the Dial function is invoked, it checks to see if a modem is installed. If there is a modem present and there wasn't one present the previous time the Dial function was invoked, then the modem is initialized. This method of initialization is unique in that it can detect modem installation that occurred between executions of the Dial function, consequently allowing the modem to be initialized during the next execution of the Dial function. Once it is known that a modem is installed, the type of modem must next be determined. For this Dial function there are two command tables defined.

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Method for Dynamically Determining Which Modem Is Installed

A method is described for dynamically determining the type of modem installed on a Personal Computer when two are supported, thereby determining the correct command table for use by autodial, without prompting the user for information. When the Dial function is invoked, it checks to see if a modem is installed. If there is a modem present and there wasn't one present the previous time the Dial function was invoked, then the modem is initialized. This method of initialization is unique in that it can detect modem installation that occurred between executions of the Dial function, consequently allowing the modem to be initialized during the next execution of the Dial function. Once it is known that a modem is installed, the type of modem must next be determined. For this Dial function there are two command tables defined. The tables are order dependent
(i.e., the first byte contains the tone dial character, the second byte contains the pulse dial character, the third byte contains the pause character, etc.). In determining the type of modem installed, a command string is sent to the modem via Com 1 and the response to the command determines the type of modem installed. The command string sent is 'AT', OEH, 'C', ODH. One modem will respond with an OAH (line feed) character, the IBM modem will respond with a '?' character, or if no modem is installed, there is a time out. The autodial routine will then use t...