[GreenKeys] Re:I hope you can help. Jan Bogue KD6EMW W15 page printer with perf

[gil smith]

Hi Jan:

At 06:46 PM 11/7/2004, Wndrrt at cs.com wrote:
>Gil, how do I get to the page on green keys where I leave my first questions?
>  Where do I sign in on this group?

Well, I signed you up already.  If you want to contact me directly, you 
would mail to gil at vauxelectronics.com, but when you email to 
greenkeys at mailman.qth.net you are posting your message to the greenkeys 
group -- so all of your messages have already been posted.  If you want to 
reply to a greenkeys post, and simply hit reply, you will only send it to 
the person that posted the message.  If you reply-to-all, or explicitly 
paste the greenkeys address into the TO or CC fields, you will reply to the 
whole group.  If it is a discussion on a topic of interest to the group, 
then please copy greenkeys in your replies.  Not only do we get to follow 
an interesting discussion, but the dialog is archived for future 
generations.  There are just under 300 folks on greenkeys, which is not 
that many.  Once we are all dead the only knowledge of these machines will 
be the manuals we have stashed (if they don't get trashed) and the 
discussions on greenkeys.


>This is what I have: "The Model 15 perforator transmitter is a combination
>transmitter and perforator with an electrically operate character 
>counter.  It
>is inserted in the base of a Model 15 printer when the Model 15 printer is 
>used
>in conjunction with a Model 19 table and a Model 14 transmitter distributor.
>When this combination of units is used together, it is known as a Model 19
>printer set.  This is what I have, but I do not have the transmitter
>distributor.  I have its base where it connects and slides in but not the 
>unit.

Do you have the wide M19 table then?  There are about four M14TD units on 
ebay right now -- you could get one and slide it in.  I have a few pics of 
the M19 at:
http://www.vauxelectronics.com/gil/tty/M19.htm

The TD is a tape reader.  The M15 has the keyboard, the typing unit (the 
page printer part), and the special paper tape punch.  The TD completes the 
set so you can both punch and read tapes.


>I can't
>figure the above out.  The transmitter distributor must transmit, but does 
>the
>Model 15 printer and keyboard also transmit?

The term transmitter distributor is misleading -- it is just a motorized 
tape reader that has that ability to key a loop with contact closures (the 
transmitter part), and performs the parallel-to-serial conversion of the 
hole patterns in the tape for sending each character (the distribution 
part).  Each row of (up to) five holes across the tape represents one 
character.  The TD senses the holes in parallel with small pins, and then a 
segmented wheel turns and the data is converted into a serial stream of 
loop-closed/loop-open contact closures.

The M15 keyboard also sends serial contact closure data.  The printer is 
driven but data on the loop, via the selector magnets.   A quick tty-101 is 
needed here I suppose:

The "loop" is a current loop, usually 60-milliamps (mA), and is usually 
"neutral," which means data bits are represented by the loop current either 
flowing (also called "marking"), or current not flowing (also called 
"spacing").  The loop itself is comprised of a voltage source 
(traditionally about 120 VDC), and a series power resistor that limits the 
current to 60-mA.  The connectors used for the loop are 1/4" phone 
plugs/jacks.  You probably don't want to use the old loop supplies, since 
they may have deteriorating rectifiers, capacitors, etc.

So this loop (voltage supply and series resistor), is connected such that 
the current is normally flowing through the loop.  TTY components are then 
inserted into the loop -- ie: they connect in series.  So the selector 
magnets of the M15 typing unit connect in series, and the loop current 
holds the mechanism in a state where it is ready to see a series of 
current/no-current bits that correspond to a character.  Then you insert 
something like the M15 keyboard into the loop, and you can type on the 
keyboard, and the characters will print on the typing unit.  You can also 
connect the TD to the loop, and run a punched tape through it -  it will 
also print on the typing unit.

In the case of the special M15 with the attached punch, the tape punch is 
mechanically driven by the typing unit, and is not an independent 
component.  So if you put blank tape in the punch and enable it, anything 
that you send to the typing unit will also get punched on the tape.

But, the typing unit, keyboard, and TD are all independent.  In fact, the 
typing unit can be on one loop (called the receive loop, usually having a 
red plug), and the keyboard and/or TD can be on another loop (the tx 
loop).  If the machine is wired for two loops, it is called "full-duplex," 
and if it is wired for one loop (ie: typing unit, keyboard, and optionally, 
the TD, all wired in series), it is called half-duplex.

gil


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