Stock tickers have been around since
the mid 1850s. It was work on stock tickers that got Thomas
A.
Edison his start. Prior to inventions on stock tickers he
was
broke. In a few years of work on stock tickers he assigned
his
rights in many patents for about $40,000 ( 66 million in 2007
dollars). This allowed Edison to setup his New Jersey labs.
Stock tickers have been developed to meet the need at the
time.
But whenever there's a stock market crash the ticker system can
not
keep up. So after Black Friday, Sep 24, 1869 a new
generation of
tickers came on line based on the Edison Universal. Ticker
machines similar to the Universal (housed in a glass dome), but
faster
were used through the market crash October 29, 1929 where they
could
not keep up.
The Western Union (they had bought out virtually all the
independent
telegraph and stock ticker companies by the start of the 1900s)
then
came out with the Ticker 5-A. Although the 5-A prints on
paper
tape in a
way to looks like the prior stock tickers and the paper tape was
used
for "ticker tape" parades, it does not use the step by step method
of
the prior tickers and so probably should not be called a stock
ticker
machine, i.e. the 5-A sounds different. The 5-A operates at
500
characters per minute maybe 8
quotations each second. In Fig 1 you can see that this
particular
one has louver vents, not drilled holes.
You could say that the Edison stock ticker was the father of the
5-A
and
the Model 26 teletype was the mother. The model 26 uses a
"pineapple" selector that's very similar to the one used in the
5-A
although they are not interchangeable. The 5-A uses a Unison
device that's very similar to the one Edison invented and was used
on
most if not all the Edison stock tickers. The 5-A runs at
500 C/M
(83 W/M) compared to the 60 W/M for the 26. Some say that
the
model 26 is newer than the 5-A but the first model 26 patent is
dated
1926. Note it's common with small arms to name them for the
year
of introduction. I wonder if that's the case with Teletype
machines with model numbers like 15, 19, 26? The 5-A patents
are
for 1938.
The following is an excerpt from a Western Union news letter (I'm
trying to get the source info). It appears to have been
written
prior to the roll out of the 5-A.
"This new ticker which will be
referred
to by the name Ticker-5-A discards the step-by-step principle on
which
the universal and self-winding tickers are constructed.
The
ticker operates on a uniform code of 8 note 1
units per character, using the start-stop principle after the
manner of
all Simplex printing machines. One impulse of the code is
used as
a start impulse and another as a stop or rest impulse.
Five units
of the code are used for the selection of the printing position
on the
type wheel and the sixth selection unit is used to determine
whether
the
character to be printed is to be a letter or a figure. The
6
selection units employ the same code as in use on the ticker
automatics
system and on the C.N.D. channel note 2
printer system. The new Simplex ticker will print on a
tape with
the same size note 3
and shape of characters as on the present self-winding
ticker. It is a type wheel machine and the driving
power
and
power for the various functions such as printing, shifting from
letters
to figures, and advancing the tape, are derived from a small
motor. The mechanism of the machine is very different from
any
previous Simplex printer and is adapted to operate at a high
enough
speed so that all of the line time possible on a single wire may
be
used to operate the one machine. It is not, therefore,
necessary
to channel note 4 the
circuit on
which these new tickers will operate.
It is difficult to present an adequate picture of the magnitude
of the
work involved in making a conversion of . . missing . .
will transmit _____ out to Other long distance circuits, and
others
will work into thicker circuit panels for which, in turn the
tickers in
the city will be operated. A Drawing #34297 is
included in
this summary showing what the distribution circuits will be
after
conversion to Tickers 5-A has been completed.
The new ticker operates on one line wire and with a current of
from 50
to 100 milliamperes. It has only a single polar line note 5 magnet. The
resistance note 6
and inductance of the line magnet are considerably less than
that of
the self-winding ticker so that a greater number of tickers of
the new
type may be placed in series in one line. It is expected
that
this ticker will handle satisfactorily, a day's trading of
between
7,000,000 and 8,000,000 note 7shares.
If
that figure is reached and surpassed, the only logical step note 8
would be to duplicate the ticker system and not attempt to
design a
ticker with a greater output than the one which we are about to
put
into service."
note 1 - The patents talk about a modification that would allow
the 5-A
to work with regular start-stop teletype machines, but that's
not the
way it was used for quotation service. There is was used
in the
5+1=6 bit isosynchronous mode.
note 2 -What is C.N.D.?
note 3 - 3/4" wide paper tape.
note 4 - multiplex
note 5 - electromagnet or polar relay
note 6 - 20 Ohms & 150 mh
note 7 - a quotation consists of the company symbol letters and
the
price in numbers. The number of shares is not on the
tape.
Most stocks are sold in blocks of a hundred shares. The
average
trade is probably some hundreds of shares, let's say 400.
8,000,000 shares would be 20,000 trades. If it takes 8
characters
for each trade that's 160,000 characters, at 500 char/min that's
320
minutes or 5.3 hours. The market may have been open for 6
hours
per day so that's a reasonable estimate.
note 8 - Whoever wrote this article did not allow for a
completely new
system, and in fact the electronic system that replaced the 5-A
has a
capacity that's so much higher it's hard to quantify.
Signaling Systems
Step by Step
The type wheel is stepped one character at a time very much like
the
second hand in a quartz clock is stepped every second. For
example if you want to print BAC the
type wheel needs to be stepped from wherever it is to the B.
Then
it needs to be rotated 1 position short of a full turn to
print A then 2 positions to print C. Most type wheels have
about
30
characters so step by step uses about 15 bits per character (half
the
number of characters).
Unison
The other problem with the
step by step method is there needs to be a way to keep all the
receiving printers in unison with the transmitter. This
problem
plagued the step by step printers and there's a U.S. patent class
devoted to Unison Devices (178/41).
T.A.
Edison invented one of the first unison devices for his Universal
stock
ticker. It uses a spiral groove on the printing shaft with a
pin
riding in the groove. If the type wheel made about 3 turns
with
the
pin in the groove the type wheel would lock up in a known
position. So to get all the machines in unison the sending
station
would send a long string of pulses thus bringing all the machines
into
unison. This could be done often, whenever there was a
break. In
normal operation every time a character was printed the pin was
lifted
out of the groove and brought back to the starting position.
Since in
normal operation the type wheel is never turned more than a single
turn
the machine would never be perturbed by the unison device.
Teletype Machines
Permutation Coding
Teletype (the common (brand) name for a
teleprinter)
machines
use
what's called permutation coding of the characters.
This
means that unlike the stock ticker machine where you just rotate
the
type wheel one character for each pulse on the line the Teletype
receiving machine needs to remember the order of the signals
that make
up one character. Budot used a 5 level binary number
system to
choose one of 32 characters which is about 3 times more
efficient than
the step by step method.
Stop/Start Idle/Printing
On/Off Mark/Space
Teletype machines also use what's called
asynchronous
which means that the timing of each character does not need to
be
related to a common clock or other characters. This is
accomplished using two states of the line: key up no signal
(open
circuit) or key down, signal being sent (current flowing).
An
advantage of On Off Keying (OOK) is that when the key is up
little or
no power is being used making it more economical than Bi Polar
keying.
When the line is idle a current flows that locks the selector so
that
it does not turn (stop condition). As soon as the current
is
broken (start bit) the selector starts rotating and as it makes
one
turn the incoming data bits setup the character that's to be
printed. After the last data bit (5 data bits on early
systems
and 8 data bits on later systems) the character is
printed. The
last bit of each character is always the current flowing
condition
which stops the selector. The stop for mechanical printers
was
commonly 1.5 or 2 bits long so that you were sure that the
selector
stopped. So to send a character takes 1 start bit + 5 data
bits +
2 stop bits or 8 bit times per character (1 of 32).
If a Teletype machine is powered but there is no line current
(like if
the line breaks) then the selector mechanism is released that
the
machine makes a lot of noise as it receives what's commonly
called a
rubout character.
For either 5 or 8 level machines during a message a large
percentage of the character time is spent in the start and stop
states.
Todays computers use this asynchronous method for the serial
(COM)
ports. But today there's no mechanical inertia problem so
only 1
stop bit is used. A common serial description is 8N1
meaning 8
data bits, No parity and 1 stop bit.
Letters Figures Shift
The 5 level system used a Figures Letters shift in order to be
able to
print all 26 upper case letters and also the digits and a small
number
of punctuation marks (no lower case letters). This system
has a
problem if a shift is not properly received, then what should
have been
letters is what appears to be random punctuation marks and
carriage
returns and line feeds in strange places or the opposite problem
where
what should be numbers is printed as letters. A good
operator can
recognize the problem and press the needed shift key or later
manually
annotate the message with the
correct characters, but it's added work. The 8 level
system
eliminated the Letters Figures shift problems and supported the
ASCII
character set that includes both upper and lower case letters
and a
host of features.
Western Union 5-A
Much of the development work on Teletype machines was done prior
to the
stock market crash of 1929 so when the 5-A was designed the
operation
of
Teletype machines was well known at Western Union since they
developed
them. The 5-A includes many improvements on the Start Stop
Teletype.
Permutation Coding
The 5-A uses a 6 bit permutation code. The 5 bits are not
probably the
standard ITA 5 level Baudot code used with regular teleprinters
and the
6th bit is used for Numbers or Letters shifting. This way
there
are no separate characters (keys) for Shift to Letters and
Shift
to
Numbers. So the locked in the wrong shift problem goes
away.
Bi Polar Signaling
Early on in telegraph history it was discovered that on long
circuits
when the key
was up there was likely to be false signaling because of
coupling from
other telegraph lines. There are ways around this
problem.
One is to
keep a small current always flowing (place a rheostat across the
key
terminals) and that tends to lower the noise. A much
better way
is to
use bipolar signaling. This can be done by using a key
with a
common
terminal, a normally open terminal and a normally closed
terminal.
With the key up a battery with it's positive terminal connected
to the
N.C. terminal feeds the line and when the key is down the the
N.O.
terminal feeds the line from the negative terminal of another
battery.
Thus there is always a current flowing. Bi polar operation
was
commonly done by using special relays at both the sending end
and
receiving end of long lines. At the receiving end the Bi
polar
relay
output would be the OOK signal to the Teletype machine in a
local loop.
Instead of using OOK the 5-A has a built-in polarized
electromagnet
that
responds to polarity reversals. In Fig 6 above you can see
a "U"
shaped magnet marked on one end "TOP" that surrounds the
electromagnet changing it from a common type that actuates with
either
polarity to one where the direction of actuation depends on the
polarity of the input current.
Coil Data
12 Apr 2007 - The Polar Relay has a resistance of 20 Ohms.
The
nice thing about it is that when 1.1 Volts is applied in either
polarity the relay actuates. This was surprising since
Teletype
machines typically work with loop voltages of 80 to 160 and
currents of
20 or 60 ma.
In order to drive the Polar Relay using a PIC micro controller I
think
a simple 3-terminal linear voltage regulator connected as a
current
source of maybe 80 ma from a 5 volt supply. An H Bridge
will
supply the polarity reversal and in addition give the option of
either
an open circuit between reversals or a short (they call it motor
braking)
between reversals. Modern cameras use an H Bridge
controller for
focus that is both small and has the needed specs.
17 Apr 2007 - the Polar relay has an inductance of 150 mH.
You would like the rise time to be less than 1% of the bit time
so the
bits have good fidelity. A bit time is 20 ms and 1% of
that is
200 uS.
For a single time constant rise time it takes 3 to 5 time
constants to
get to almost 100% so the needed time constant is about 40 us.
The needed R = L / 40 us = 3750 Ohms or 3730 Ohms resistor + 20
ohms in
the coil. To get 100 ma through 3750 ohms says the loop
voltage
needs to be 187 to 375 volts. But that's if using a
voltage
source. The actual voltage across the coil in a steady
state
condition would be 375 V * 20 /3750 = 2 volts. At
the
instant the loop is closed the current in the coil will be zero
and
will exponentially rise with the time constant L/R, so in
200 us
(5 time constants) will be very close to steady state, i.e. very
close
to 2 volts.
So
instead
of using a high voltage powers supply and
a big series resistor why not just use a 5 volt power supply
and a
current source? This is not the way teletype machines
are
normally driven so maybe there's something I'm missing.
18 Apr 2007 - On the
Greenkeys
mailing
list
I learned how to figure out the answer. The problem occurs
when
the circuit is opened and the coil contains energy that needs to
be
dumped as fast as possible. If a diode or Transil is
placed
across the coil then the time constant is long (R is low t.c. =
L/R). So you want to operate the coil in as high a voltage
circuit as needed to get the desired off time. The needed
voltage
is given as:
V = L * dI /dT which in the case of an older RTTY machine
running at 100 baud with 10% distortion might be V = 4 H * 60 ma
/ 1 ms
= 240 Volts. But for the 5-A running at 50 baud it works
out to V
= 150 mH * 60 ma / 2 ms = 4.5 Volts. If a higher voltage
is used
the off time gets shorter.
The loop is still
best
implemented as a current source to keep the loop
resistance as high as possible for the turn on condition.
A
current source becomes a low resistance if it's saturated.
For
example an analog current source set for 100 ma from a voltage
source
of 20 volts is trying to drive a coil that at t=0- has no
current. At t=0+ the coil current is zero and the current
source
can only become a short to try and supply the needed 100
ma. Once
the actual coil current gets near 100 ma then the current source
starts
backing off and then looks like a high impedance. But
during the
critical transition time it was a low impedance that slowed down
the
turn on time constant to Lcoil / Rcoil, which in this case is
150 mH /
20 Ohm or 7.5 ms, way too slow.
Loop
Voltage
|
R
100 ma
|
TC
ms
|
5*TC
|
200
|
2k
|
.075
|
0.37
|
100
|
1k
|
0.15
|
0.75
|
75
|
750
|
0.2
|
1.00
|
50
|
500
|
0.30
|
1.50
too slow
|
With a loop voltage of 75 and a 750 Ohm resistor the coil
charging time
constant will be 0.2 ms for (5 * tc) turn on time of 1 ms.
75 v * .1 amp = 7.5 watts which since this is a bi polar system
is on
all the time.
25 May 2007 - I've found a couple of ways of driving the
selector
electromagnet.
Full H-Bridge - This
uses two
half bridges where a half bridge consists of two electrical
switches
stacked one on top of the other. The top switch is
connected to
the 80 volt power supply and the bottom switch to ground.
The
common point of the switch is connected to one of the selector
electromagnet inputs. Another half bridge is connected to
the
other input. Now when the left half bridge has the top
switch on
and the bottom switch off and the right bridge has the bottom
switch on
and the top switch off the polarity is in one direction.
When all
the switches are flipped the polarity is flipped. The
forbidden
condition is that you do NOT want the top and bottom switches in
a
half bridge both on at the same time since this would short the
power
supply to ground. When N channel MOSFETs are uses as the
switching elements the gate bias for the top switch needs to be
higher
in voltage than the source of the device, i.e, it needs to be
higher
than the HV power supply voltage. IR and others make half
bridge
drive ICs that have a small switching power supply to do this
and in
addition have circuitry to prevent the shoot through that can
short out
the power supply.
2T2R - I made up the
name for
Two Transistors and Two Resistors almost full bridge. Here
the
two bottom switches are MJE340 high voltage power NPN
transistors but
the two top switches have been replaced with power resistors one
of
which sets the loop current. See
RTTY
the
Easy Way
(BARTG). When a transistor is turned on that line wire is
at
ground. When a transistor is turned off that line wire
goes
through the resistor to the HV power supply. But notice
that for
the transistor that's turned on the resistor above it has the
full
power supply voltage across the resistor. So this circuit
requires a transformer (
Triad
N-68x) that can deliver a little more than twice the loop
current.
Good information about the HV supply is on the
TTY Connect
Teletype
Interface System
web page, but unfortunately this is a Neutral or On Off Keying
type of
interface that's common in the U.S. the RTTY the easy Way design
is
from Britain where polar drive is the standard.
Unison
The 5-A does NOT use
a
start and stop
pulse. (the first patent below says this, but I've
heard
the 5-A
tickers are run using the option in the second patent with start
and
stop pulses) Every line polarity
change is considered a clock edge. Thus the 5-A can operate
like
a
synchronous data protocol saving the time needed for the start and
stop
bits. One of the patents calls it "self synchronous".
But
the 5-A is not what's today called a synchronous system since it
can
stop, pause and restart at any time between characters.
Since
there are no start or stop bits it's easy to combine signals using
a
multiplexer so that they all can be sent on one channel.
The unison device is very much like the Edison unison. It
consists of a worm gear on a shaft with a pin riding the
groove.
If for example the machine is plugged in and turned on with no
connection to the bi polar magnet the the pin will continue moving
the
the groove and after a few turns will lock up the selector.
At
this point the motor is turning but the selector mechanism is
quiet. The preferred method of obtaining unison is to supply
marking current polarity to the line when no characters are being
sent
for maybe 5 character times thus bringing the machine into
unison. Then when character bits are sent the 5A keeps in
unison.
The second patent mentions that it's desirable to not stop sending
thus
allowing the unison device to activate, but better to keep the
line
active with data so that the cams stay synchronized. How
that's
done without printing anything is not specified. There
are
no non printing characters on the type wheel that could be
used.
You wold not want to print a blank character because that would
feed
the paper tape. What's needed is to have the line current
reverse
in such a way that the printer keeps in sync yet does not trigger
printing. Maybe flipping the polarity once every word time, i.e.
once
every 300 ms? Not an issue since the 5-A does use the start stop
method.
Pipelined Printing
The Teletype machine has the time from the last data bit plus the
stop
bit(s) plus the start bit to complete printing a character.
But
the 5-A has no stop or start bits and so would have difficulty
printing
characters at a rate of 500 per minute if it all had to be done in
less
than a bit time. This problem is solved by printing the
character during the incoming bits of the following
character.
This way there's about 5.5 (110 ms) bit times available to print
the
character
before the next character needs to get latched.
It turns out that the 5-A knows the type wheel position after 5
bits. The sixth bit either chooses column 1 or column 1 on
the
type wheel by shifting the wheel or not shifting. The sixth
bit
can therefore be used as a signal to transfer the 5 bits from the
input
selector bars to the memory bars thus pipelining the
character.
Now the input selector bars are ready to read the next input
character
and the type wheel has a full character time to move to the next
position.
Timing
A comparable teletype machine would use the same bit time of 20
ms. The computation goes like this:
20 ms per data or start bit and 28.4 ms for a stop bit so a
character
length is 20 ms + (5 * 20 ms) + 28.4 ms = 148.4 ms / character or
6.7
characters per second, which times 60 seconds in a minute is 404.3
characters per minute. In Morse code when looking at timing
the 6
letter word PARIS is used. So to get from characters per
minute
to words per minute we divide 404.3 by 6 which comes out 67 WPM
called
66 WPM.
For the 5-A using the same bit time of 20 ms * 6 data
bits
= 120 ms / character or 8.33 characters per second times 60 is
"500
Characters per Minute" and is the number often mentioned about the
speed of the 5-A. Dividing the CPM by 6 characters (letters)
per
word gives 83 Words per Minute. But the 5-A is not run in
the
isosyncrhonous mode.
I'm not sure if my 5-A has the optional parts to make it into a
start
stop machine as is described in patent 2135375 or if it's an
isosynchronous type like in patent 2117241. 18 Apr 2007 -
It's
looking more and more like this machine, and most of the 5-A
machines,
were configured for start stop operation and used the USTTY aka
ITA2
alphabet for letters, but the figures may be unique? There
are a
number of different type wheels that can be used on the 5-A.
The
one called financial or business has all the fractions in 1/8
steps to
do stock ticker work. There are other versions for weather
that
have the circles with different patterns inside to represent
different
cloud types, there is also a wheel for sports reporting.
Line Connection
The cable to the line has three wires:
White - ???
Red and Black to polar coil.
The Bi Polar relay appears to be 20 Ohms resistance. Red to
Black
is 20 Ohms, but none of the wires connects to the chassis.
The second patent shows a circuit (2135375 Fig 22) that describes
how
the output of a 6 level tape reader can be fed through some relays
and
a rotating selector to drive a single wire with a bi polar signal.
Type Wheel
It's very important that the type
wheel print the letters at the top of the tape and the numbers at
the
bottom. This is to allow quick eye scanning of a tape to
separate
or find a stock symbol. Later machines tried to use two
different
colors of ink and print in a straight line, but the separation
works
the best. Today the electronic scrolling stock ticker
displays
still use the offset letters and numbers for the same reason.
After the combined paper tape canister
and ink roller box is removed (take out three screws) you can see
the
type
wheel. The type wheel is connected to the selector cage
"pineapple" which
determines where the type wheel will be when it's time to print a
character. The selector cage has a notch in it that takes up
2 of
the 34 index positions that are possible so only 32 index
positions are
used and 2 are always skipped.
|
|
Type
wheel
photo 1
|
Type
wheel
photo 2
|
The type wheel is a smooth surfaced aluminum turning that has a
rubber
strip of characters attached to it's circumference. On
either
side of the of seam are the characters "." in both the letters top
row
and the figures bottom row. I'm guessing that the characters
on
either side of the seam fall into the notch on the selector drum
and so
are never printed. That leaves 32 rotational positions that
can
be used times a letters or figures shift for a total of 64
possible
characters. They are arranged in a strange way as follows:
s
e
|
0
0
|
0
1
|
0
2
|
0
3
|
0
4
|
0
5
|
0
6
|
0
7
|
0
8
|
0
9
|
1
0
|
1
1
|
1
2
|
1
3
|
1
4
|
1
5
|
1
6
|
1
7
|
1
8
|
1
9
|
2
0
|
2
1
|
2
2
|
2
3
|
2
4
|
2
5
|
2
6
|
2
7
|
2
8
|
2
9
|
3
0
|
3
1
|
s
e
|
a
m
|
3
1
|
3
0
|
2
9
|
2
8
|
2
7
|
2
6
|
2
5
|
2
4
|
2
3
|
2
2
|
2
1
|
2
0
|
1
9
|
1
8
|
1
7
|
1
6
|
1
5
|
1
4
|
1
3
|
1
2
|
1
1
|
1
0
|
0
9
|
0
8
|
0
7
|
0
6
|
0
5
|
0
4
|
0
3
|
0
2
|
0
1
|
0
0
|
a
m
|
.
|
S
|
n1
|
U
|
I
|
E
|
.
|
A
|
.
|
F
|
N
|
K
|
C
|
D
|
n2
|
J
|
R
|
Y
|
H
|
Q
|
P
|
Z
|
T
|
W
|
L
|
X
|
M
|
.
|
V
|
B
|
O
|
&
|
G
|
.
|
.
|
s
|
.
|
1
4
|
9
|
5
|
.
|
1
|
c
|
6
|
_
|
n
3
|
3
|
4
|
0
|
_
|
_
|
3
4
|
8
|
*
|
_
|
7
8
|
1
8
|
1
2
|
_
|
5
8
|
$
|
_
|
3
8
|
2
|
-
|
B
|
7
|
.
|
Notes: I have numbered both ways so that when I'm trying to
figure out the coding one of them should be correct.
WRONG - Baudot was a hand
entry code
so is not in binary order.
n1 is a symbol that looks like a capital letter "P" with a small
letter
"r" underneath.
n2 is a symbol that looks like a letter "c" sitting on top of a
vertical stroke "|". (cents?)
n3 is a symbol that looks like an upside-down "5". (English Pound
Sterling?)
Rearranging in alphabetical order gives:
A
|
B
|
C
|
D
|
E
|
F
|
G
|
H
|
I
|
J
|
K
|
L
|
M
|
N
|
O
|
P
|
Q
|
R
|
S
|
T
|
U
|
V
|
W
|
X
|
Y
|
Z
|
1 |
2 |
3
|
4
|
5
|
6
|
7
|
8
|
9
|
_
|
N
3
|
_
|
$
|
_
|
-
|
7
8
|
*
|
3
4
|
s
|
1
8
|
1
4
|
3
8
|
1
2
|
5
8
|
3
4
|
7
8
|
The first 5 bits of the code for a vertical pair in either table
above
will be the same. This does not match any of the TTY codes
where
Figures 1 is paired with letter Q. That's
because it's
ITA2.
This code was developed by Baudot for input using two
fingers of the left
hand and
three fingers of the right hand and so the letters are NOT in
binary
order.
Ticker Paper Tape
Probably: 3/4" wide suitable for printing (not oiled like
for
punching). Max outside diameter for a new spool 7".
Core
center hole about 7/16". Paper tape is available from
Claus Studios
he uses a band saw to cut a slice off a longer roll.
Patents
| Patent
1821110 |
|
|
WU 5-A
1821110 (pdf) Selecting and Printing
Mechanism, Sterline Morton, Howard L. Krum, Edward E. Kleinschmidt
(Teletype), Sep 1 1931,
178/33R ; 101/93.19; 235/429
This patent looks like a much
better
fit than 2117241 & 2135375 and is much earlier.
Has two selector mechanisms, the first is set by the code and
the
second is set by the first. This way a character can be
printing
while the next character is being decoded.
1884754 (pdf) Printing Telegraph, H.L. Krum (Teletype), Oct 25
1932,
178/28
; 400/186; 400/257; 400/62 - stock or news broad printer - moving
type
wheel
has a strong similarity to the 5A
stock
tape printer
2117241
Telegraph Printer, R.F. Dirkes, E.R. Wheeler, V.R. Kemball
(WU),
May 10, 1938 178/34 ; 178/38 (18 pages)
This is not a step-by-step printer
but
instead a Start-6 unit bi-polar code-Stop type printer.
Since stock quotes are almost continuous instead of actually start
-
stop type operation this printer can keep running and only correct
the
speed as needed. Eliminating all the stop-start cycles makes
operation quieter and is easier on the mechanical parts.
A type wheel is used in the 5A that similar to the type wheel used
in
the prior stock tickers and not a drum like in the Teletype
machine. But instead of pulsing the type wheel one step at a
time
it's spun by a motor until it hits a stop that selects which
character
gets printed.
Although this patent is for a tape printer many of the features
are
specified for either a tape or page printer.
178/34 = Telegraph - Printing - Page - With Type Wheel Recorder
178/38 = Telegraph - Printing - Page - With Type Wheel Recorder -
with
Type Wheel
2135375
Telegraph Printer, V.R. Kimball, R.F. Dirkes, E.R. Wheeler,
(WU),
Nov 1, 1938, 178/34 ; 178/38; 370/305
Included in this patent are a couple
of
alternate cams that can be used so that this printer will properly
respond to start stop type telegraph signals, although that would
mean
running a a slower speed. Also that instead of letting the
unison
device activate by not sending anything for a few character times
it's
preferable to keep the line active to keep the cams turning.
178/34 = Telegraph - Printing - Page - With Type Wheel Recorder
178/38 = Telegraph - Printing - Page - With Type Wheel Recorder -
with
Type Wheel
370/305 = Multiplex Communications - Low Speed Asynchronous Data
System
(e.g., Teletypewriter Service) - Synchronizer - Start-Stop
Model 26
1595472
Telegraph Apparatus, H.L. Krum (Morkrum), August 10, 1926, 178/27
1632297
Printing Telegraphy, E.E. Klindschmidt (Morkrum), June 14, 1927,
178/17B ; 199/18
1635129
Telegraph Transmitter, C.L. Krum (Morkrum), July 5, 1927, 178/33R
;
400/478; 400/479
D112119
Printing Telegraph Apparatus Cover, G.R. Lum (Bell Telephone &
Teletype), November 8, 1938, D14/472 ; D18/12
1766713
Transmitter, E.E. Klindschmidt (Teletype), June 24, 1930, 178/27
2180360
Printing Telegraph Apparatus, H.L. Krum (Teletype) , November 21,
1939,
400/141.1 ; 400/156.1; 400/164.2; 400/164.4; 400/70
2193970
Printing Telegraph Apparatus, H.L. Krum (Teletype), March 19,
1940,
400/141.1 ; 400/70
2224546
Printing Telegraph Apparatus, H. Lottermann (Teletype), December
10,
1940, 400/142 ; 400/175
2230463
Printing Telegraph Apparatus, C.A. Levin (Teletype), February 4,
1941,
178/27
2247408
Printing Telegraph Apparatus, A.H. Reiber (Teletype), July 1,
1941,
178/29
2250012
Web Guide, W.H. Eddy (Teletype), July 22, 1941, 400/615 ; 226/23
Loop Supply
Label:
TELETYPE
Input A.C. Volts: 115, Cycles: 50-60, Watts: 35
Rectifier: REC 45
Output D.C. Volts: 120/75 Amps. Cont: 0.2, Amps Int: (blank)
Supplied by
TELETYPE CORPORATION
Chicago, Illinois, U.S.A.
Manufactured by
North Electric Co., Galion, Ohio, U.S.A.
|
This has REC 45 fitted, not
the
REC43 2 terminal socket.
|
|
Uses a strange AC 2 prong
plug.
The DC output is on a 3 socket cable.
Dwg No. WG-1606-8
|
TM-2215 Teletypewriters TT-5/FG and
TT-6/FG (Teletype Model 15 Maintenance) June 1951, 423 pages has
information on the power supply and on the
255A polar relays.
Links
