The general format for this plugin is:

{DATACHANNEL(various_parameters="")}
body input to capture variables passed to the profile
{DATACHANNEL}

The most typical body input option allows data to be typed in to an input field prior to the datachannel being executed and the profile being run and has the format:
variablename,some text to describe the input required for this variable

Where variablename can then be used as a profilerequest variable in the profile that is run and/or in wiki page content templates used to populate new wiki pages. The format for use in profiles is: $profilerequest:variablename$VARIABLE NOT SET$
(the second set of text between the $ characters provides default text if for some reason the variable has not been set - it doesn't have to be CAPS ! )

But one small problem is that any input made this way will always end up as text that is passed to whatever Tiki object is used in the profile - and this will be a problem if the end storage is a tracker date field. The input process therefore needs to be 'amended' so that the resultant input is the appropriate Linux integer representing the date.

This can only be done by a JS 'hack' at present but this is easily done by placing the following JS code in the "Custom javascript:" area of the Customization tab of the Look & Feel admin screen:

$(document).ready(function () {
  var $dateField = $("");
  $("[name=confirmdate]").hide().parent().append($dateField);
  $dateField.tiki("datepicker", "jscalendar",
        {altField:"[name=confirmdate]"});
});

Where you will need to change the name elements from confirmdate to whatever you have called your variablename.

This will then automagically make the input entry field into a datepicker function and this then makes the data entered into the appropriate Linux integer.

From Tiki 15 onwards, it is possible to use a custom Smarty (ie. HTML) template to create the form that is used to collect user input for the datachannel. This provides for complete flexibility. To do this, specify the "template" parameter as the filename of the template file (relative to the templates folder), and start off with a copy if template/wiki-plugins/wikiplugin_datachannel.tpl. Remove the "foreach" section that creates the fields normally and then simply put your fields in. A very basic example:

        Select your favorite juice:
        
                Apple
                Orange
        
        

                
                
        

Note that you still have to provide the names of the fields you are passing in the body of the DATACHANNEL plugin, even though the labels are not needed, for example:
juicetype
instead of something like the following which would generate a text field with the "Juice Type" label:
juicetype, Juice Type
but even if you did that it would not matter. It would just ignore the label provided.

Available from Tiki9, if you want to provide fixed input that is hidden, you can simply specify:
variablename,hidden=value
This could be useful when used in conjunction with Wiki Argument Variables, for example:
creator,hidden=

Available from Tiki6, a very useful option for automatically generating profilerequest variable content is to use the external option which has a plugin body format as follows:
variablename,external=tagId

This allows data captured in input forms 'earlier' on the page to be automatically assigned to the variablename. For example if a TRACKERFILTER is used on the page prior to the DATACHANNEL plugin any of the selected filter fields can be used as 'externals' since the filter fields are all given Id tags of f_nnn where nnn is the tracker field#.

An example of this might look like:

{TRACKERFILTER(trackerId=8,filters=100/d, fields=98:99:100, noflipflop=y, status="opc", showstatus="y", action="Show filter results", showlinks="n")}{TRACKERFILTER}

Followed by:

{DATACHANNEL(channel="channelname" buttonLabel="run profile" emptyCache="none")}
variablename,external=f_100
{DATACHANNEL}

An extension of the 'external' option was introduced in Tiki15 (and backported to Tiki 12.4 and 14.0) to allow any data previously displayed on the page, as long as it had an individual html Id tag assigned to it. This then allows simple constructs that tabulate data with html tags or more useful filtering of trackers can be carried out using TRACKERFILTER, TRACKERLIST and LIST etc., with appropriate templating, to display sets of data with Id tags embedded that then allow 'external' data to be very flexibly passed to the profile.

The format for this type plugin body input has a modifier added to the end of the standard 'external' format as follows:
variablename,external=tagId,text

It should be noted that all types of input can be mixed and matched in a single datachannel usage eg you can use something like this to capture various 'external' data as well as typed in data

{DATACHANNEL(channel="channelname" buttonLabel="run profile" emptyCache="none")}
variablename01,external=var01Id,text
variablename02,external=var02Id,text
variablename03,external=f_100
variablename04,external=var04Id,text
variablename05,external=var05Id,text
variablename06,type in some text for this variable06
variablename07,external=var06Id,text
{DATACHANNEL}

See in action:
http://profiles.tiki.org/Project_Management&highlight=datachannel
http://profiles.tiki.org/Learning_Center&highlight=datachannel