FTP ASCII-mode: Over the Internet does FTP *really* only transfer 7 bits per character? Is it really 1/8 faster than binary-mode?

I read that FTP ASCII-mode only transfers 7 bits.  Which statement is more true?:

1) It only puts the lowest 7 bits in 8-bit byte "containers"... simply the most significant bit (msb) is always hardcoded to 0?

2) It literally bit-shifts 7 bits into 8-bit containers... 7 bits of first char + 1st bit of second character in first byte, then last 6 bits of second character and first two bits of third character in the second byte, etc.

Isn't the Internet a "byte-oriented" beast?

In the ancient era of computing where they had devices called "modems" I can imagine that it would actually only send 7 bits per character... you needed to squeeze as much over the phone line as possible... but I find it hard to believe bit shifting occurs over the Internet.
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ZuZuPetalsAsked:
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giltjrCommented:
No.  In ASCII mode FTP uses NVT ASCII, which is based on 8-bit characters.

Read section 3.1.1 Data Types.

http://www.w3.org/Protocols/rfc959/3_DataTransfer.html


FTP did not (actually no application did) control the number of bits that were transmitted over the link.

When using a modem in asycn mode typically 10 bits were sent for every chracters:

 1 start bit
 7 data bits
 1 parity bit
 1 stop bit

There were other options, such as no parity and/or 2 stop bits. So the min. number of bits was 9 and the maximum was 11.  I have no clue how, but there was actually an option for 1 1/2 stop bits.  Not sure how to get half a bit.

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giltjrCommented:
Oh, just as a F.Y.I, ASCII mode transfers are actually a tad bit slower than binary transfers.

This is because the sending side must translate each characters from local format to NVT ASCII and the receiving side must translate from NVT ASCII to local format.

Whereas when using binary no translation is done.
Dave BaldwinFixer of ProblemsCommented:
In the 'modern' era, all fax machines have modems in them.  Fax modems are just a specialized case of modems.  And all serial communication including ethernet is bit oriented, shifting one bit after another.  1 and 1/2 bits in dialup modems is just a timing thing.  And all of it is converted back to bytes, words, etc.
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