
k:I3——4l‘9(3(3
ASCII,
BAUDOT
AND
MORSE
KEYBOARD
ONNER’S
MANUAL
TABLE OF
CONTENTS:
Description
. . . . . .
.................. 3
Commands . . . . . . .
.... . . . . . . . . . . . . .
... 5
Specifications.....................
7
Dperation.......
. . . . . .
............. 9
General
Operation..................
12
Operation
on
12v. . . . . . . . . .
......... 15
Circuit
Functions . . . . . . . . . .
........ 15
Ca1ibration..... . . . . . . . . . . .
........ 15
In Case
of
Difficulty
. . . .
.......... 16
Limited
Warranty.......
. . . . . . . . . . ..
16
Program
Changes
and
Revisions...... 16
Assembly Drawings
and
Schematics... 17
Code Practice
Lists...... . . . . . . . . ..
Appendix
A
CIRCUITS AND EPROM
CONTENTS
COPYRIGHTED
1980,
ALL RIGHTS RESERVED
CURTIS ELECTRO
DEVICES, INC.,
BOX
4090,
MOUNTAIN
VIEW,
CA 94040

*
3.8 *'#’* # *
*I*
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Your KB—490O is a
product
of the
computer
age.
Unlike its
predecessors
the KB—42OO AND
KB-4800,
this unit does not use discrete dedicated
parts
to
perform
its function.
Instead,
it
employs
an
"all
purpose"
IC called an
integrated microprocessor.
This
device
does
nothing
itself,
however,
when
provided
with a
list of
instructions,
it will
carry
them
out
and in so
doing,
accomplish
the
objectives
of the
programmer
who devised the set of instruct‘
ions.
The KB—4900 uses a
microprocessor
called the 5035
(developed by
the
Intel
Corporation).
The 9035 contains an 8-bit
central
processor
unit
(CPU),
512 bits of
random access
memory
(RAM),
27
input—output
lines (1/0) and
an B~bit timer/event
counter.
For
instructions,
we use the
2732 (Ultra-Violet) Eraseable
Programmable
Read—Dn1y Memory
(EPRDH). It can
contain
as
many
as
4,096
individual
instructions
composed
of
32,768
individual bits. The
sending
buffer and
message storage
are
implemented
in another
powerful
IC,
the 2114. This
Random—Access
Memory
(RAM) will
store
512
Esbit
bytes
in its
4,096
read‘
write
storage cells,
and
last,
but not
least,
the
venerable 9044
single
chip
keyer
IC
provides
the Morse
code
generation
in
order to free the
processor
for more
complicated
tasks. For
those
of
you
interested in
statistics,
the
circuitry
in
the KB—4900 contains
approximately
100,000
individual
transistors.
The
program
for
the KB—4900 uses most
of the
4,096
instructions
possible
from the
2732. From
a
library
of 90
individual instructions
recognized by
the
microprocessor,
the
program
is
built-up
into
a
sequence
that
provides
the
function of
the KB—4900.
The
microprocessor
winds its
way through
the
program
at the
rate of
400,000
instructions
per
second.
And,
while it looks
as
though
things
are
being
done all at
once,
in
reality they
are
being
done
one—by—one.
The
processor
does
everything serially except
that it handles
all data in
groups
of
eight binary digits
called
bytes.
The
processor
is
unbelievably busy
while the
unit is
operation,
executing
the
prescribed
program
at the 400 KHZ
rate. It is not
unlike a
juggler
keeping
many plates
spinning
at
one time.
Though
we have
only
one
juggler,
there is a whole
lot of
activity
going
on. In the
case of the
KB«4900,
it
may
be
sending
DU,
accepting
new
key
inputs,
assigning spaces
in
the
sending buffer, unloading
the
sending
buffer at
some other
point, running
the buffer
meter, running
the
speed
meter,
holding
the
PTT line
down,
watching
for buffer
overflow, keeping
track of the
time.
incrementing
the serial
number,
and
scanning
the
keyboard
for new
commands....400,000
times a
second without mistakes!
The
program
for
the KB—4900
consists of 78
pages
of
single spaced
text. It
took
nearly
six
months
of
writing,
testing
and
debugging
to
get
the
program ready.
we
hope you
enjoy using
the
system
as much
as
we
enjoyed
designing
it,
If
you
have
suggestions
on how we
might
improve
the
unit,
don’t
hesitate to
call or
drop
a line.
(D

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Duner’s
Hanual..............
. . . . . .........
. . . . . . . . ...Revised
01-23-81
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F:EE¢§1_LJF?EEE3-
ISENDS
XSENDS
ISENDS
ISENDS
XSENDS
KSENDS
MORSE
FROH KEYBOARD
HORSE FROM PADDLE
KEY,
MANUAL KEY
BAUDOT
CODE FROM KEYBOARD
ASCII CODE FROM KEYBOARD
I)EE£3(3F?
I F31'I EJFJ-
OR BUG
TRUE RANDOM
HORSE FDR CODE PRACTICE
PSUEDO RANDOM MORSE IN 8~l5OO CHAR.
LISTS OF 5-LETTER
GROUPS N/ANSWERS
Sends Morse
code from the
keyboard
or
from an external
paddle
key
at
any speed
selected
by
the
speed
control.
Analog
controls
(potentiometers)
sidetone
pitch
and sidetone volume.
An
analog
meter readout of buffer
status
the
fullness of the
sending
buffer which
(overflow
lamp
and
pitch change
on
Horse
A "BUFFER HOLD" function allows break—in
key
is
operational during
the hold.
An
analog
meter readout is also
provided
readout.
This is calibrated from 5 to B0
either
keyboard, paddle
initiated
keying
are also
provided
for
weight,
continuously
indicates
can
contain as
many
as 256
characters.
signals
nearly
full buf#er)
operation.
The
paddle
for Morse code
speed
upm
and is effective
for
or random code
practice.
Push—to—talk control is
provided
for transmitter
switching
in all modes.
PTT release is
delayed
0.5
Special prosigns
AS,SK,BT,AA,KN,
KA
plus
commercial.
Four
programmable message
memories
(A,B,E
&
D)
seconds {or convenience.
most
European
and
are
provided.
These
can consist of one to four
messages
whose total is 256
characters.
Messages
are called
via the
sending
buffer.
partitioned, meaning
that “B”
imum use of the
memory
storage.
The memories
may
be
"chained"
Memories
always
starts wherever
The {our memories are soft
"A" ends to make
max-
"C. and "D"
via the buffer.
(Warning lamp
for overflow
during
load is
provided)
(3)
follow in
the same manner.

Automatic bu11t'in
messages
are
provided
as follows:
CG CG DE
(message
A)
(i.o. "KbKU")
CD
TEST DE
(message
A)
DE
(message
A) (This is the "ID"
key)
QRZ
(message
A)
(Note that these are
appended by programmable
message
“A“)
Two
key
lockout
operation
of
keyboard prevents
lost
characters
during
"burst"
typing.
A "DELETE"
key
allows
correction of errors
prior
to transmission.
An automatic
incrementing
serial number from 0 to 9999 is available
for insertion into
the
sending
buffer or the
message
memories for contests
which
require
sequential numbering. Leading
zeros are not transmitted.
A
repeat
Function allows
repetition
of
any
o¥ the Four
message
memories
a5ter a
presettable
period
of from 1 to 99 seconds.
9 real—time clock
option
allows
generation
of a time transmission
(24-hour
Format,
1.e. 21:42) in
Morse,
Baudot or ASCII. Time can be
inserted in the
sending
buffer or
any message memory.
Time is sent
as 21R24 in
Morse,
21:24 in ASCII and Baudot.
BAUDOT
CODE:
Baudot (S—level) TTY code is transmitted ¥rom
the
keyboard
at
50
wpm
standard
speed.
(45.45
baud)
Both RTTV
and
Cw
ID are
provided
("ID“
key)
High voltage
&OmA.
loop keying
transistors are built into the unit.
Provisions are made for
mixing
receiver audio and
keyer
sidetone For convenient
monitoring.
Carriage return,
line feed and "LTRS" are sent
automatically
after 63 characters and a
space
have occurred on a line. After 70
characters,
the Function is initiated without
any space being present.
This makes nice
looking copy
at the
receiving end,
with the
carriage
return not
breaking
words.
Also this
frees the
operator
4rom
worrying
about
the
carriage
return.
All
up
and down shift is handled
automatically.
In
addition,
a
dounshift occurs on
every space
to
quickly
clear
any
garbles
in
recept-
ion.
As
with Horse
transmission,
included are the
sending buf§er,
the
programmable message memories,
the
automatic
message sequences
plus
the
"DELETE" function and
KUS
(Key-DperatedASwitch)
control.
ASCII:
Same as
Baudot above
except
that Functions
involving up
and
down
shift (FIGS and LTRS) are not
required.
Transmission
speed
is 110
baud.
Both
upper
and lower case are
generated (upper
case
by shifting)
G "CAPS LOCK“ function
allows
transmission of
capital
letters
only.
(4)

NURSE PRACTICE:
Mode 1: Random
length groups
of random
characters
are sent
in a
never
repeating sequence
at the
speed
selected
by
the
speed
control. Extra
spacing
between characters can be selected
for easier
study
when
trying
to
make
large speed
increases.
Mode 2: Psuedo random
five character
groups
are
sent, however,
unlike the
above
true random
generation,
this second mode
sequence
is
always
the
same
and answer lists can
be
provided.
There are
eight
lists available and are
called
by
placing
the number "1"
through
“E” in
message memory
"A". If
any
other character is
placed
in
message
memory "A",
the
mode 1 random Horse
will be sent. The
sending stops
at the
end of each list. To
restart,
use a
system
reset and restart the
program.
with
both
modes, you
can
insert extra
space
between letters
by pressing
the "CTRL"
key
followed
by
the "5"
key.
Also,
with both
modes, you
can eliminate numbers and
punctuation
by
placing
an "N" after the “R” or number "i" thru "8" in
message memory
"A".
C3C3P1P1F§FJI)S3- - _ - - - - - - - - - - - - - - - - - - - - - -
- -
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I
I
1 (NOTE: "CTRL-X“
MEANS PRESS THE "CONTROL"
KEY, RELEASE,
THEN PRESS
"X") X
I (SHIFT/X MEANS HOLD THE SHIFT KEY WHILE DEPRESSING THE "X")
3
8 X
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NURSE HDDE: CTRL-1
(Automatic after
system
reset)
Unmarked
prasigns:
:
SH/A
SH/Q
:
SH/E
N: SH/N
D: SH/D
U:
SH/U
CH:
SH/C
ATTENTION:
SH/T
HYPHEN: SH/H
UNDERLINE:
SH/L
UNDERSTDDD:
SH/K
SEPARATION:
SH/S
BAUDDT NUDE: CTRL—2
CR: SHIFT/.
LF:
SHIFT/,
LTRS:
SHIFT/;
BELL: SHIFT/AS
RTTY ID:
"ID"
CH ID: CTRL-"ID"
(S)

ASCII
MDDE:
CR:
LF:
BELL:
RTTV
ID;
CH
ID:
RANDOM CODE:
SLOW NUDE:
NUDE l:
MODE
PAUSE:
ALL MODES:
LOAD MESSAGES:
READ SERIAL NR:
PRESET SER. NR:
TRANSHIT TIME:
PRESET TIME:
REPEAT MODE:
PRELOAD
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MODE:
"A":
"Bu:
"C":
"D":
CTRL—3
SHIFT/.
saxrr/,
SHIFT/AS
"X9.
CTRL-"ID"
CTRL—4
(standard
CTRL-5 (extended
Place
any
letter other than
'
thru
"8" in
message
"A"
Place
letter "1"
through
"E" in
message
memory
"A"
Press SHIFT and hold
one
second;
to
release, press
SHIFT
again
spacing)
spacing)
CTRL-At,
(Note:
send
message,
Message
then
ETRL
again
(for
message
"A”)
"A"
normally
will consist
of
your
call letters)
ETRL—Bt,
send
message,
then CTRL
again
(for
message
"B")
As above for "C" and
"D"
(Lamp
lights
two
characters
before full.
In
addition,
the buffer meter indicates
the
amount
of
message memory
storage
space
used)
(Message
"A"
must
be
programmed
be+ore
message "B",
any change
[of
length]
in
"A"
will affect
message
"B").
The same is true of "C" and
"D",
i.e.
program
"A"
first,
next,
"C" next and "D" last.
Any
later
change
of
length
in
a
preceding message
will
disrupt
the
following messages.
also
nsu
SHIFT/6 (This does not increment the
number) SHIFT/5
can be inserted
in
message
memories "A"
through
"D" where
each use will increment the number.
CTRL—b followed
by
four
digits
(most
significant
first).
Use
CTRL—I to
increment,
CTRL-D to
decrement
SHIFT/At
CTRL-7 followed
by
four
numbers (NSD first).
started at zero seconds as last number
Clock is
(LSD) is entered.
Preset
delay
interval in number oi seconds
by pressing
CTRL—-(dash)
{allowed
by
two
digits
(NSD first).
Messages
A!
through
D!
will
then
repeat automatically
until
the
SHIFT
key
is
pressed (during delay)
to release and reset
delay
to zero.
The overflow
lamp lights
during
the
delay
interval for
monitoring.
Type SHIFT/SPACE,
then CTRL to release
(Lamp warning
for overflow). Can also use SHIFT/SPACE
bar.
"Au!
nan‘
ucu’
nun‘
(6)

CR
MESSAGE
(CG CG DE
[message
A]);
type
SH/"C"!
CD
TEST
MSG (CG TEST DE
[message
AJ); type
SH/"D”t
“ID”
"ID"
key
QRZ
MESSAGE:
SH/"B"!
PRELUAD
BUFFER: SHIFT/SPACE
bar (CTRL to
release)
HOLD
BUFFER: SHIFT/SPACE
bar
(CTRL to release)
DELETE
LAST
KEY: "DELETE"
key
DELETE
LAST WORD:
"DELETE"
key
(from
sending
buffer
only)
MESSAGE
RESET:
RESET!
BUFFER
RESET:
RESET!
SET
SPEED:
Press ETRL—B
and
adjust
speed pot,
any key
releases
TUNE:
Press
CTRL~9,
SHIFT
to release
(gives
continuous
dots)
(3
Note:
Keys
followed
by
an "3" are
the NHITE
keys.)
E3F’EZ(3
IIF7 I C3¢§"T'I
CJBJSS
- - - - -
_ _ _ _ - - -
- - - - -
- - -
SPEED:
MORSE RANGE:
S TU BO
NPM
(Upper
end user
adjustable
higher
or lower)
BAUDDT:
45.45 baud
(60
upm).
8 unit
code: 1
START,
5
DATA,
2 STOP
ASCII: 110
baud. 11 unit
code: 1
START,
B
DATA,
2
STOP
SENDING
BUFFER:
256
keys
MESSAGE MEMORIES:
256
keys total,
soft
partitioned
into
Four sections
FIXED
MESSAGES:
CD CG
DE
(msg
"A")
EQ TEST DE
(msg
"A")
DE
(msg
"A")
DRZ
(msg
"A")
Incrementing
serial
number
24vhour
tine
MONITOR:
Internal
sidetone
generator
and
speaker,
volume and
pitch
adjustable
KEYBOARD:
54
key alphanumeric
plus space
bar, punctuation
and
prosigns
(AA,KN,BT,AR,AS,SK,KA
plus European
A,A,E’,D,U,CH
AND
N.
also
commercial
"ATTENTION", hyphen,
underline,
"UNDERSTDOD"
and
"SEPARATIDN“).
Gold inlaid
key
contacts
individually replaceable.
Sculptured
and tilted
two-shot molded
keycaps.
One character
produced
per key
depression.
Debounced
and
"TNU—KEY LOCKOUT”.
MANUAL
KEYINB:
with external
straight
key.
PADDLE KEYING:
with external
paddle key,
iambic
with dot and
dash memories.
(7)
55%:
=§;v
_.,,,.,d,,_H.W°,
5”/7’
=
/F7?
=
/477$/I/7'iaxV

INTEGRATED CIRCUIT CDHPLEHENT:
B035,
2732.
2114,
74LS75
(2),
74LS1b4,
lLD74(3), B044, 741-LS175,
7805
Euxth real-time clack
option
HC14518B (3)1
INPUTS:
RECEIVER AUDID...B Ohm!
PADDLE
KEY.......Single
or twin lever
(optically
xsolated)
MANUAL
KEY
....Telegraph key
(optically
isolated)
12
Vdc....
.....10 T0 14 Vdc 3 500 mA.
OUTPUTS:
KEYLINE... .
300V,
500mA max.
mercury relay
PTT......
....300V,
500mA
max.
mercury
relay
LDDP......
.....30OV,
l00mA
max.
(optically
isolated)
TTL TTY... .....TTL
level,
sink or source 5 MA
SPEAKER...
.....8 Ohms or
headphones
POWER REQUIREMENTS:
1l7Vac S0—60
HZ,10VA
OR 12Vdc 9 500 mA.
234Vac
50-50 HZ
by special
order
SIZE:
12" wide x B-1/2"
deep
x 4-1/2"
high.(30.4B
X 21.95 x
11.43
cm)
WEIGHT:
5.5 lbs.
(2.49kg)
FINISH:
Panel is
light grey,
bottom and
side
panels
are
textured black.
(lettering
in
white, yellow
and red)
PANEL
CUNTRDLSI
Speed, weight, pitch
and volume
controls;
tune/self—test
switch, power switch, system
reset
switch,
overflow warn-
ing lamp,
illuminated
speed
and bu+{er
status meters.
REAR
PANEL:
Jacks For
l2Vdc,
TTY
loop,
TTY
TTL level
output,
paddle
key,
manual
key,
transmitter
keyline,
transmitter
PTT,
receiver
audio,
and external
speaker
Dr
headphones.
117
Vac
receptacle
and ¥use.
(SPECIFICATIONS
SUBJECT TO CHANGE
WITHOUT NOTICE.)
(8)

C3F°EZF?é§1']iC3FJ-
- - - - -
--- - - - -
- - - - - - - - - -
Note:
Use shielded cable
{or all interconnections
between
the KB—4900
and other
units
including
the
keys.
!!X38XtllMPDRTANTtItltX
Always
connect
all the
transmitter
cables before
connecting
the
ac
line
to the KB~4900.
This
prevents problems
from
minute ac
leakage
from the
ac line
bypass capacitors
in the
KB—4900
Also,
make sure
the unit is
equipped
for the line
voltage you
are
using,
i.e.
either
117 DR 234 Vac.
Place
the "TUNE/DP/SELF—TEST"
switch
in
"SELF-TEST"
until
you
are
ready
to
go
on the
air. "SELF—TEST"
disables
the
keyline
and
PTT
relays.
CW KEYBOARD:
Connect
the
keyline
of
your
transmitter
to the
jack
marked "XMTR“ on
the rear of
the KB—4900. Connect
the PTT
line of
your
transmitter
to
the
jack
marked
"PTT" on the rear
of the
KB—4?00 (or
you
may
use
a
separate
hand or
foot switch
for PTT as
some
operators
prefer).
Connect
a
paddle key
and a manual
key
to the
respective
jacks
on the
rear
o4 the unit if
you plan
to use them.
Set
the SPEED control
at
midrange.
the WEIGHT
control at full
CCN,
the
pitch
and
volume controls at
midrange
{or
start-up
unless
you
have
already
set them where
you
like. Use the
HEIGHT control
very
sparingly
ii at
all. It is
normally
used
only
at
speeds
up
to about 20
Hpm
except
to
compensate
for slow
acting
transmitter
keying.
Use of
more than a
very
slight
weight
addition is
not a mark
of excellent
operating practice
and
Mr. Horse
didn’t intend it. But it
will
smooth—up
slow
speed
transmission
a
bit.
Connect a cable
from the 8 ohm audio
output
of
the receiver to the
jack
marked “RCVR” on the
rear of the
KB—4?O0 if
you
intend
to use
the "SPKR”
jack
of the
KB—49OO to listen
to mixed sidetone
and
receiver
audio. Note
that the RCVR and SPKR
jacks
are
simply
connected
in
parallel.
The KB—4900
comes on in the cw
mode. To
go
to the Cu mode from
either the Baudot
or ASCII
mode, thpe
CTRL-1. If in the
random
practice
modes, press
the
SYSTEM RESET switch.
Set
the desired
speed by
either
sending
characters
and
adjusting
as
you
listen or
type
CTRL-B
and
adjust
the SPEED
pot
until
the
desired
speed
is
read on the
speed
meter. Press the
SPACE
key
to
release
from this mode.
Preset
the time and serial number
if desired
by
referring
to the
GENERAL
DPERATIDN
section.
Similarly,
preload
the
message
memories
as described in
the GENERAL DPERATIDN
section.
(9)

Move the "TUNE/DP/SELF—TEST"
switch
to “UP”
and the transmitter
will
key
in the
CM mode.
Vou
may
tune
the
transmitter either
by
typing
CTRL-9
or
by
placing
the
"TUNE/OP/SELF-TEST"
switch in
"TUNE".
CTRL-9
will
give
you
a
string
o4
dots to avoid
overheating
the
transmitter
final
stage
during
protracted
tuning.
The
"TUNE" switch holds
down
both
the
keyline
and
the PTT line.
By
sending
either
from
the
keyboard
or the
paddle,
both
the
keyline
and
PTT
circuits will
be
activated,
the PTT line
will wait about
0.5 seconds
before
opening
for convenience.
The PTT line
is not activated
by
the
manual
key.
BAUDOT KEYBOARD:
Connect
a cable from
the
loop
circuit of
your
printer
and TU
(Terminal
Unit or
modulator/demodulator)
to
the
jack
marked
"LOOP" on the KB—4900.
This
jack
is isolated
From
the chassis
and the internal
circuitry
of the
KB—4900. It
will work
with either
polarity
o{ dc and
is rated to
key
up
to 300
Vdc at
l00 mA max.
Host amateur
loops
are
approximately
l9O
Vdc at 60 mA.
Make sure the
TU
loop
is
deactivated
during
hook-up,
otherwise
the 190 Vdc
will
appear
at the
exposed
end of
the
loop
plug
causing
a
potential
electrical
shock.
Also,
connect a cable
from the
PTT line and
keyline
of
your
transmitter
to the
respective
jacks
on the rear
of the KB-4900 (PTT
to
"PTT",
KEYLINE to
"XHTR”.
To
go
to the Baudot
mode, type
ETRL-2.
Now, typing
on the
keyboard
will
key
the
loop
circuit.
To
go
on the
air,
place
the “TUNE/DP/SELF~TEST"
switch in TUNE
before
starting
transmission.
This will close
both the
keyline
and PTT circuits
placing
your
transmitter in
the RTTY mode
where the
characters
are transmitted
by
FSK
(Frequency
Shift
Keying).
Type
just
as on
a normal
typewriter,
all
LTRS and FIGS shifts
are done
For
you
automatically
in addition
to all end~of-line
carriage
returns
and line feeds.
At the end
of
your
transmission,
return the
"TUNEIOPI
SELF—TEST"
to "UP".
Note that at the
beginning
and end
of
your
transmission
and at ten
minute intervals
during
the
transmission, you
are
required
to
send
your
call
letter identification.
Pressing
the
"ID"
key
will
send
the ID
in
RTTY, pressing
"SHIFT/ID“ will
send
your
CH ID
over the
loop
circuit.
This assumes
you
have loaded
your
call
letters into
message
"A" as described
in the GENERAL
OPERATION section.
If
you
experiment
with the code
speed,
you
will find a
speed
(around 13
wpn
for Baudot)
where the
printer
will
print
all O’s
during
the
ID.
I¥
you
want KDS
(Keyboard
Operated
Switch)
carrier
control,
connect
the
KB-4900 PTT
output
to control
your
transmitter
keyline
and/or
PTT
line,
a
0.5 second
delay
on
PTT
dropout
will
allow
momentary
pauses.
You
will need to "diddle"
with
the "LTRS"
key
to
prevent
dropout
otherwise.
(10)

TTL TTY
Output:
If
you
want to drive
your
external
RTTY
equipment
with a TTL
level instead of the current
loop, open
the unit
by removing
the four
screws on
the bottom and remove the
jumper
plug
from
P3 on
the
keyboard
PCB. This
puts
a
good
TTL level on the rear
jack
marked
"TTL TTY". This
signal
will
also
satisfactorily
drive
some EIA level
receivers. If
you
don’t remove the
jumper,
the
high
level
at the rear
jack
will be invalid
ASCII KEYBOARD:
Same
as above for Baudot
operation except
that
you
can send both
upper
and lower case
after
pressing
SHIFT/CTRL.
The unit comes
up
in the CAP
LUCK node where all
alphabetic
characters are transmitted
as
capital
letters. when not in the CAPS
LOCK
node,
use the
SHIFT
key
for
upper
case the same as on a
typewriter.
DUDE
PRACTICE:
You have
a choice of two
general
modes of random code
practice.
The first
is
true random where the
sequence
is
in
groups
of random
length
which
never
repeat exactly
the same
way.
Call
up
this mode
by placing
an "R" in
message
memory
"A" and
typing
CTRL—4 or
CTRL—5 (see below).
The second mode is PSUEDU RANDOM code
where the
groups
are
always
five
characters in
length
and will
repeat exactly every
time
they
are
played.
There are
eight
different lists called
by placing
a
number
from 1 to B in
message memory
"A"
and
typing
CTRL—4
or CTRL-5 (see below).
The
eight
code lists are available for
checking. They
run about 1500 characters
each.
To halt the code
practice
(for chow call
etc.), press
the SHIFT
key
for one second. To restart where
you
left
off, press
the SHIFT
key
for
one second
again. (Incidentally, halting
code
practice stops
the real~time
clock also.
Practice will
stop
at the end of each list. For the true random
mode,
practice
will
continue
indefinitely
until
you
hit the SYSTEM
ESET.
For
normally spaced practice,
use CTRL-4 to commence the
code,
for code
with extended
spacing
between
letters
(quasi-"Farnsworth Hethod"),
type
CTRL-5 to commence the
practice.
If
you
desire
only
the
alphabetic
characters
(no numbers or
punctuation),
load an "N" in
message
"A" after the "R" or number loaded for true
random
or
psuedo
random
practice.
The
speed
of
code
practice
is set
by
the "SPEED" control and
the
speed
meter indicates the
speed
of character
generation.
Note that
ypu’re
cheating
in the extended
practice
mode so the
wpm
indication
isn’t
correct
though
the
speed
of individual letters is correct.
Use SYSTEM RESET to exit from the
practice
nodes.
(11)

C3EEDJEEF?£§l_
CJF>EEF?£)‘r.IC3fQ- - - - - - _ - - - - - _ -
- - - -
Usually
the first
step
when
you begin operation
is to load at
least
message memory
"A" since
you
will
use it
constantly. Preloading messages
"B“,"C"
AND "D"
is at
your option.
For contest
use,
the
messages
to load
here will be obvious
except perhaps
for the serial number which
will
be
inserted
in some
fashion in
memories
"A“,“B"
UR "C" such as "UR
NR
--—-,
QSL?"
or
something equivalent.
The serial number will increment
by
one
each
time it is
used in
message
“A",“B“,”C"
DR
"
'.
You
may
also imbed
the
time in one o¥ the
messages
if
you
like. For
example,
you might
prepare
the
message
"TIHE HR l5 -—R——
GMT 12/24/30". For the other
messages,
you
can load in
sequences
like
"TNX FER RPT
—
UR SNN IN NEST
PDDUNK,
TX
“
NAME
HR IS TEX
~
TEX
—
RIG IS 50 AND SO RUNNING FIVE WATTS
TO A FUURTEEN
ELEMENT
YAGI
‘
SD
HW? ". You are limited
only
by your
imagination
and
the 256 characters
total
you
can load in the {our memories.
PRELDADINE
THE ESSABE
MEMORIES:
The
procedures
for
loading
each of the
message
memories
"A"
through
"D"
are
the same
except
that
you
must
proceed
From "A" to "B" to "C" to "D".
The reason For this is
that "B" starts at the end of
“A”,
"E" starts
at
the end of "B" and "D" at
the end of "C". This method is used to
get
maximum utilization
of the available
memory.
If
you change
"A","B"
or "C" (unless the
length stays
the
same), you
must redo
the
following
messages
also.
Note that
you may
have one
long message,
{our shorter
ones,
one short and
one
long
or
any
combination of one to four
messages
the total of
which
may
not exceed 255 characters
(keys).
Normally, message
"A" will consist
only
of
your
call letters.
To
prepare,
type
CTRL—Al (the white
"A“), type
your
call letters
and
then hit the
"CTRL"
key again
to
release from the load mode and end the
message.
You can include
any key
or shitt combination in
the
message including
the time or
incrementing
serial number. But not
including
the fixed
messages
(CD,CD
TEST.
QRZ AND THE ID’S)
Prepare
the
other
message
memories "B"
through
"D" the same
way using
white
keys B,C
AND D.
when
you
have
space
for
only
three
characters
(keys)
left
in the
TOTAL
memory,
the OVERFLDN
lamp
will
light
and
you
will
have to
stop
accordingly.
You
may
have to redo
message
"D" if
you’ve stopped
at an awkward
place.
Abort from the load
by terminating
with
a "CTRL"
key
stroke.
Note that the serial is called
by typing
SHIFT/6 and the time is called
by typing
SHIFT/At (white
key).
Put a
space
after
the serial and before
and after the time.
PRESETTING THE SERIAL NUMBER:
Type
ETRL-6 and
type
four number
digits starting
with the most
significant number,
for
example type
the 3 first if
presetting
the number 3456 or
type
the 0 first if
presetting
0135. or
type
three
0’s first if
presetting
0003 etc.
Normally,
you
will start
a
contest
by
presetting
0000.
Always type
in four numbers. The load terminates
on the fourth number. Vou can check
the
preset
number withour
in-
crementing by typing
SHIFT/b. This combination also loads
the serial
number
into
any
of the
message
memories.
(12)

when
the serial
number is
accessed via
a
message memory,
it increments
before
transmitting. i.e.,
if
you preset
to
0000,
the first number sent
via the
message
memory
will
be 1 (OOOX).
If
you
have a
problem
during
the
contest with the numbers
getting
out of
line,
you
can increment the
serial
by
typing
CTRL—l
or decrement
by typing
CTRL-D.
If the
serial number
gets
too far out of
line,
use the
preset
to
get
back on track. Note
that
the
decrement command takes
a
finite
part
of a second to
finish,
the OVERFLUU
lamp
will
iight
during
the decrement as a reminder.
SETTING THE TIME:
If
you
have the real-time clock
option, you
will want to set the time
after
you
have
turned on
the
unit. (The clock
only
runs when the unit
is
powered,
either
by
ac or 12 Vdc. Because this clock is not as
stable as a normal
timepiece,
it
may gain
or lose
time even if
left
powered.
To set the
clock, type
CTRL—7 and
type
in the time in 24 hour format
i.e. 7:00 PM is 19:00.
Type
the first three numbers
starting
with
the most
significant
("1” in the case of
17:00,
"O" in the case of
06:15,
etc.)
Type
the fourth number at the 0 seconds time and the
clock will
be
exactly
set. This means
you
will
normally
wait for the
next minute to come
up
before
hitting
the last
number,
Vou must
always
type
four numbers and the
preset
terminates
automatically
on the last
number.
To send the time over the
air, type
SHIFT/At(white ’'A"). You
may prefix
and suffix
a
space
as if it were a
single
letter
in the
text,
or a
more
elegant way
is
to imbed it in a
message
memory
with
the
PST,EDT,EHT
or
what have
you plus
the date. (TIME
HR
IS
12:45 PST
-
12/24/80)
You embed
the time
during
the
message
load
by simply typing
SHIFT/A! (white
“A").
USING THE FIXED
MESSAGES:
There are
four fixed
messages
in the KB-4900 which are
coupled
with
message memory
"A". These are:
1. CH CD DE
(message
"A") Note
that
message
"A" must be CALL
LETTERS
in these
messages.
This
message
is called
by typing
SHIFT/Ct (white "C")
2. CD TEST DE
(message
"A").
Type
SHIFT/D3
3. DE
(message
"A").
Type
"ID" (Use SHIFT/XD for CH ID
during
RTTY
operation.
4. DRZ
(message
"A")
Type
SHIFT/Bl (There is no "DE" in this
message
for
brevity.
(13)

PRESETTING
THE MESSAGE REPEAT DELAY:
You
can
repeat
the
message
memories
simply
by striking
the white
message
key repeatedly
or
you
can
use the
delay
mode for
delayed
repeats
of
from
1 to 99 seconds.
To load the
delay figure
in
seconds,
type
CTRL-- (dash)
and
then
type
two numbers
representing
the
delay
desired (in seconds).
Type
the most
significant
number First (the TENS
digit).
If the number
is less
than 10
you
must
type
the
leading
zero.
Now when one of
the four
message
memories
are called
up,
it will
repeat
continuously
at the interval
preset
until aborted
by hitting
the
SHIFT
key
while the
delay
is
underway.
The
DVERFLDN
lamp lights
during
the
delay period
as a convenience.
DELETE
FUNCTION:
Vou can delete
the last WORD
typed, assuming
it hasn’t started
transmission, by
hitting
the
"DELETE"
key.
SHIFT/RESETl(WHlTE KEY) has
the same effect
if
you
prefer.
Each
time
you
hit the "DELETE"
key,
the last word (back to
a
"space"
will be deleted.
If
you
are
loading
the
message
memories,
or
setting
the time or the
serial;
the
"DELETE"
key
will delete one
CHARACTER
per depression.
ABORT MESSAGE
MEMDRV DR BUFFER TRANSMISSION:
Hit the
white reset
key
and
the
message memory
and buffer
will be
reset. The
message
memory
is saved but buffer contents
are lost.
SVSTEH RESET
would do the same
thing
but the mode would default
to CM.
HDLD TRANSMISSION:
Transmission
may
be
temporarily
halted
by typing
SHIFT/SPACE. This allows
the
receiving
station to
break for a
repeat
etc. You can use the
paddle
during
the hold if
you
like. The transmission
will be continued when
you
hit the "CTRL"
key.
This feature can be
extremely
useful
in traffic
handling.
The "HOLD" is effective
in all modes
using
the
sending
buffer.
SYSTEH RESET:
when
you
turn on
your KB—4900,
the circuits are
automatically
reset
and the
unit comes
up
in the Horse
keyboard
mode. The time and serial
registers plus
the
message
memories will have
garbage
in them
as their
contents
,by design,
are not affected
by
a reset. When
power goes
off,
their contents are of course lost.
Normally,
the
only
time
you
have to
operate
the
systee
reset
(except
For exit trom the code
practice
modes)
is,
if for some
reason,
such as a
power
transient
or severe r.f.
interference,
the
processor
goes
bananas. If this
happens,
the
keyboard may
be
locked,
or
sending
the
wrong
keys
or there
may
be
a
string
of unwanted
characters
transmitting.
In
any event,
you
will Feel
you
have lost
control
of
things.
If
this
happens, hitting
the SYSTEH
RESET
will
make
every-
thing
right again.
The time and serial
may
be scrambled
depending
how
the
processor program
self destructed
during
the crash. The
program
is
permanently
locked
in the EPROH so no
permanent change
will
occur.
(14)

OPERATION UN +12 VDC:
Your
KBv48OO can be
operated
from
+10 TD +14 Vdc
batteries or
from
a mobile
power system.
You can
also use a
+12
Vdc
battery
continuously
connected for
battery backup
in case
of ac
power
failure. With the
battery
voltage
at or
below about
12
V
there should
be little drain
as
long
as the
unit is
powered
by
ac.
Connect the
battery
cable to the
KB-4900 before
applying power
to the
other end or
you may
get
a
spectacular
short if the
center
pin
of
the RCA
plug
hits the
(grounded)
chassis! In
any event, place
an
inline 1
Ampere
fuse in the
battery
supply
line for
safety.
You can reduce
the
battery
current drain
by
half
by
removing
the
meter illumination
lamps.
CIRCUIT FUNCTIONS:
The KB—4900
consists of
an 8035
microprocessor.
a 2732 32K
bit EPRDH
for
program
storage
and a
2114 4K bit RAM for
sending
bufier and
message
memory storage.
An
B044 is used for the
keyer
section.
A 74LSlb4
is used for the
keyboard
"X" matrix
scan. Two 74LS75’s
are
used to latch the
EPRDM and RAM
addresses.
A
74LS175 serves
to latch
the lower four
hits of
port
2. Three lLD—74
dual
optical
isolators isolate
the
paddle
key,
manual
key
and RTTY
loop.
A 74LS3O
B-input
NAND
gate
is used to
detect a hexadecimal OFFH on
the
latched address
lines.
This is NORed with
the write
signal
from
the
processor
to
develop
a strobe for
writing
to an
external
parallel
ASCII
monitor.
If
you
have
the
real-time clock
option.
three
HC1451B dual BCD
counters
divide the
4OOkH2 ALE
frequency
to 0.4Hz. This
signal,
{ed to the
B035
port
17, provides
the clock
reference.
CALIBRATION:
Normally, your
KE—49OO
will not need
calibration
over the life of
the
unit
however
you may
touch
up
the
settings
if
you
desire.
1.
Haximum
speed
limit:
This
parameter
is set
by
adjusting
a
trimmer
labled "R1" and
located on
the small PCB
located
on the
rear
panel
of the unit.
It is the
only
trimmer on
the
board and is
accessable
by
simply
removing
the
four screws
holding
the
bottom
wrap-around.
You can
adjust
the maximum
speed
(when
the
speed pot
is
full clockwise)
by
rotating
the
trimmer
until
the
speed
meter reads
your
desired
maximum.
2.
Speed
meter
calibration:
A trimmer
on the
keyboard
PCB controls the
calibration o!
the
metering
circuit.
Connect an
oscilloscope
or
pulse
measuring
counter to
pin
14 of the 8044
IC. Set the
speed
pot
to
give
a
reading
of 48
ms. for
cycle
length
when
the dot
key
(or
CTRL—8) is
depressed
(dot is 24
ms., space
is 24
ms.). Then
adjust
the
trimmer
marked “s” on
the
keyboard
PCB. This trimmer
is
accessible from
the
top
or
bottom of the board.
hen the
speed
meter
reads 50
upm,
the
adjustment
is correct.
(You will NOT HEAR
dots
during
this test
if
you
use CTRL-E.
They
are muted.)
(15)

3.
Buffer meter calibration: Another trimmer
on the
keyboard
PCB controls
the buffer meter
calibration. Press SHIFT/SPACE(bar)
to
place
the
unit
in a
preload position.
Then
type
keys
at random
until the buffer
fills and the DVERFLDN NARNING
lamp
lights.
Hit three more
keys
to
completely
fill the
buffer,
then
adjust
the trimmer marked
"b"
on
the
keyboard
PCB until
the buffer meter
indicates "I00". Press
the SYSTEM RESET to reset the
unit. Note that this
trimmer is also
accessible from the
top
or bottom of
the PCB.
I bl CIKXESEE EJF7 I I F7F='I CZLJL_1'\’-
- - - - - - - - _ - - _ _
Field trouble
shooting
is best
accomplished by
substitution of
IC‘s based on an educated
guess
of
possibility.
Or
just
blind
substitution if
no
localization can be made. The
only component
not available in the field is the EPRDH which
must be ordered from
the
factory.
The B044
may
also be
obtained from the
Factory.
D4
course,
any component may
be ordered from us if
desired.
If
you
can’t locate the
problem,
call or
write us for
help.
we'll
suggest
the
best
way
to
proceed, possibly
requiring
the return of the
unit.
L. IP4 I'TEEI) UJ€§F?F?£§hJ1'\(_ - -
- - - - - - _ -
- - - - - - - - -
He will
repair any
defect caused
by components
or
workmanship
without
charge
for labor or materials for a
period
of 90
days
after
you
receive
the unit. You will be
responsible
for
shipping
both
ways
from our
factory.
After 90
days,
we can
quote
the estimated
repair
cost after
examining
the unit
according
to
prevailing wage
and
material costs.
Although complicated
in
Function,
the KB—4900 is
quite
simple
in
execution so
repairs
should not
be too difficult. In
addition,
all lC’s are
socketed for
ease of
servicing.
The one
event which ruins a lot
of amateur
equipment
is the
electrical storm.
This sometimes turns
part
of the
circuitry
into soot
and
invariably
burns out
every
semiconductor. If not too
severe,
we can
sometimes
repair
the
unit
at an
acceptable
cost. In
any event,
see
if
your
homeowner’s insurance
covers such
things
so
you
can
easier
decide what
you
can bear. The best
insurance
against
electrical
damage
is to
disconnect the ac
power
from the
station
completely
(Pull the
main
plug,
don’t
depend
on
the switch) and
ground
and
disconnect
your
antennae from
your
equipment.
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C:F1£\PJC5EEE3 FNPJI)
F?EE\J I 53 I
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The
program
in
your
KB-4900 is
contained in an EPRGH.
This device can
be
erased
with
ultraeviolet
light
and
reprogrammed quite
easily.
If
we
make
product updates
of the
program,
we will
correspond
with
you
to ascertain
if
you
desire
the
update.
If the
update
is a
correction o6 a
problem,
the
only
cost would
normally
be a
small
mailing charge.
If
the
update
is
a
signiicant
improvement,
there
may
be some
reasonable
charge
depending
on the
nature of the
change.
You
may change
the (socketed)
EPRDH
yourself
or if
you
don’t
feel
up
to
it, you
can
always
have
us do it. The
only
difficulty
is
inserting
the
device into the
24
pin
socket without
mashing
the
pins.
Otherwise,
it’s a five
minute
job.
CURTIS ELECTRD
DEVICES, lnc.,
Box
4090,
Mountain
View,
CA
94040
Tele: 415 494
7223 TNX: 910 373 2017
Cable:
CURTIS,
PALD
ALTO,
CA
Shipping
address: 4140
Transport
Ave.,
Palo
Alto,
California
94303
(16)