I would introduce the acronym OTG in parentheses here (right after "On the Go"), so that people that are reading on know what it stands for.

You don't need to break the line here prematurely (this is not a man page ;-)).

same here.

There must be an empty line here to separate the </para> from the new <para>.

s/the need special/the need for special/

Pull this line up into the one above.

The indentation seems off here. The <scree> needs to be on the same level as the <para>s above and below.

Make an empty line before <screen> appear here. ;-)

/as laptop/as a laptop/

the "pstat -t" would be better when wrapped in <command> tags. You can leave out the " then. Also, remove the "the" and "command" before and after it. You can rewrite it like this:

Use <command>pstat -t</command> on the host to list the terminal lines.

or

List terminal lines on the host using <command>pstat -t</command>

Another empty line here.

One more empty line at this position.

Another ... (you know what I mean). ;-)

And another...

s/as laptop/as a laptop/ (same as above)

s/open connection/open a connection/

s/Putty/<application>PuTTY</application>/

s/Putty/<application>PuTTY</application>/

Same here for Putty.

I think it would make sense to wrap the cfumass into <filename> tags here, as the sentence is referencing the file/script directly.

And another empty line...

Time for an empty line...

use of?

maybe we should add something like "or a combination thereof"?

probably drop "the usual host mode". client port implies it's not host mode.

too many clauses in this sentence

You're probably right, but I'm not sure how to split it.