🚀 go-pugleaf

Writes Timo Salmi (ts@uwasa.fi):

> I would like to turn to another question, which relates to the 
> Telix host mode (hostplus).  Does anyone know how to make it work 
> over a direct connection (two PCs connected via a cable).  I have 
> not (yet?) found it covered in the hostplus documents, and 
> experimenting has not been successful.  

I don't think the Telix Host Mode is intended to manage a direct 
PC-to-PC link. It is intended to manage a modem, for incoming 
calls. It controls the line with modem commands and relies on 
modem signals and responses.

> Procomm plus (I have 1.1A), incidentally, has a setting to enable 
> a direct connection, and it works.  

Yes. And several other programs can be used in that way, too. For
example, you can use the Jmodem external protocol program as a
self-standing PC-to-PC file transfer utility. Especially v1.20, a
5 KB executable written is assembly. Later versions, rewritten
in C, and are slower and bulkier. It should also be possible to
use DSZ in the same way. And several other programs.

> So does laplink over the same cable. 

Yes, Laplink is intended SPECIFICALLY for that purpose.

> This obviously means that the problem is with the Telix hostmode.

It is not a problem, actually, the Host+ doesn't appear to have
that feature, and there is no good reason why it should.  Most other 
Host Modes do not have it either. They are meant to work with 
modems, not directly over a cable. 

If you need a direct, PC-to-PC file-transfer program, there's 
nothing better, faster or cheaper than ZIP, by Meyer. It is a superb 
utility.  It will squeeze all the speed the PC UART can accommodate
using a simple null-modem cable. ZIP dates back to 1987 or so. The 
latest issue is v1.6, dated November 1992.  (The name trademark
predates Katz', by the way).

Meyer's ZIP demonstrates that you can indeed write comm software (in 
assembler) that can drive the PC port to its maximum speed, up to 
about 115,000 bps on a direct connection, without need of any stupid 
"buffered UARTS" (16550).  It incorporates its own error-
correction protocol and even has a Server mode.  Gosh, you can even 
adjust its menu colors!

 (Next time somebody tells you that you need to install a 
 16550 buffered UART in your computer in order to stop having 
 "lost characters" at 14,400 bps, tell him to go take a look 
 at Meyer's ZIP program to learn how to write efficient serial-
 port management software that doesn't loose characters at 
 115,000 bps through a plain UART! )

ZIP is free for personal use. And so is Jmodem.