Protocol Options

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Protocol Options
ASCII File Transfer Protocol*:
The term ASCII protocol is a bit of a misnomer, because in an ASCII transfer neither side of
the link is following well-documented rules. An ASCII protocol is really just a convenient
way of transmitting a text file.
It is difficult for the receiver to know when an ASCII transfer is over because there is no
agreed-upon method for indicating termination. The ASCII protocol terminates on any of
three conditions: when it receives a ^Z character, when it times out waiting for more data, or
when the user aborts the protocol.
The following parameters control the ASCII protocol:
Inter Character Delay
Determines the number of seconds or ticks to delay between characters during an ASCII file
transfer. Usaully set to 0.
Inter Line Delay
Determines the number of seconds or ticks to delay between lines during an ASCII file transfer.
Usually set to 0.
Delay in Seconds or Ticks
Specify whether the value given for Inter Character Delay and Inter Line Delay is in Ticks or Seconds.
A Tick is the time unit used by the communication software (ASYNC Professional). Accounding to the ASYNC Pro documentation it roughly equates to 1/18 of a second.
However, this seems to be system dependant. End user testing may (will) be required to determine actual value required.
Ascii EOF Timeout
Determines the number of seconds before an ASCII transfer is automatically terminated.
Because most text files are terminated by a ^Z character (ASCII 26), the ASCII protocol
closes the file and ends the protocol when it finds a ^Z. If the received file isn't terminated by
a ^Z, the ASCII protocol determines the file was completely received after a specified
number of seconds elapse without receiving any new data.
Close Port Timeout
The number of seconds to delay the actual closing of the communication port in use after the ASCII protocol signals
transmission complete ON THE CODESHARK side of the communication stream. Some serial port servers (ie Ethernet to Serial devices) require this
timer to prevent port closer from terminating serial transmission from the actual serial device to the receiving device.
Usually set to 5.
CR Translation / LF Translation
Computer systems sometimes use different character sequences to terminate each line of a
text file. Most PC software stores both a carriage return <CR> and a line feed <LF> at the
end of each line. Other systems store only <LF> or only <CR> at the end of each line.
The ASCII protocol provides a number of options for translating from one end-of-line
sequence to another, both when transmitting and when receiving. When performing these
translations, the <CR> and <LF> characters are treated separately, based on the values
assigned to the CR Translation and LF Translation.
CR translation determines the end-of-line translation mode for carriage returns <CR>, possible selections include:
None: the default, do not modify the character.
Strip: strip the character from the data stream
Add LF after CR: adds a line feed character <LF> after each <CR>.
Add CR before LF: currently treated as None.
LF translation determines the end-of-line translation mode for line feeds <LF>, possible settings include:
None: the default, do not modify the character
Strip: strip the character from the data stream
Add CR before LF: insert a <CR> before each <LF>.
Add LF after CR: treated as None.
* Information displayed here taken from the Async Professional 4 Reference Guide, available from:
AysncPro Documentation
CNC
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