Re: HDLC via V.24 or b-channel?
Tilman Schmidt <[email protected]>
| Newsgroups | gmane.linux.isdn.i4l.user |
|---|---|
| Message-ID | <[email protected]> |
Am 15.03.2012 16:51, schrieb Jens Bürger: > What I am not sure about is the question, how HDLC might have been > implemented via "V.24"? Would it be possible to do this via a standard > (USB-)RS232-interface? V.24 (or equivalently, RS232C) is just a mechanical and electrical specification for a serial interface. It doesn't say anything about the structure of what's finally going to be transmitted over the lines thus specified. In particular, it doesn't specify whether the transmission is to be synchronous or asynchronous. Nothing in the standards forbids using a synchronous link protocol like HDLC over V.24. In fact, the ubiquitous Intel 8251 was originally called USART (Universal *Synchronous* Asynchronous Receiver Transmitter - my emphasis) because it could do both. However, whether - the "8251"s inside today's chipsets still retain that capability - USB serial adapters can do synchronous transmission at all - Linux serial drivers support any of that is for someone else to answer. The last time I dealt with HDLC myself was when I coded the bytewise HDLC frame encoder/decoder for the Gigaset driver, and that was for ISDN B channels, not for V.24. HTH T. -- Tilman Schmidt E-Mail: [email protected] Bonn, Germany Diese Nachricht besteht zu 100% aus wiederverwerteten Bits. Ungeöffnet mindestens haltbar bis: (siehe Rückseite) _______________________________________________ isdn4linux mailing list [email protected] https://www.isdn4linux.de/mailman/listinfo/isdn4linux
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