Вот вариант. http://www.unicoi. …king_product_suite.htm
Из переписки:
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Here is our Single Product, Single Processor pricing:
Fusion TCP/IPv4: $7,500 USD
Fusion PPP (PPP, PAP, CHAP): $2,100 USD
20% of the license fee for a year of technical support.
One thing I need to mention is that our PPP requires the Fusion TCP/IP stack since there is no standard API for PPP to interface with different BSD stacks.
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Yes, you are correct. We do not have a standard API in our PPP so that it can be used with any BSD stack but that’s not to say it can’t be done.
You are more than welcome to do it but my engineers would not be able to support you. Is this something you would be interested in?
This price is for ANSI C source code.
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Связь с модемом - реализовать несколько функций последовательного порта, всё элементарно, в документации хорошо расписано, что да как. Но к сожалению, для привязывания к другому TCP/IP стэку придётся потребуется в исходниках копаться.