The TI-74 "BASICALC": A Modern 8K Pocket Sized Reincarnation Of The CC40
Thanks to Charles Good for donating this article.
Reviewed by Charles Good Lima Ohio User Group April 1992
Accessories and Peripherals
Mass Storage and CC40/TI74 Software Compatibility
General Conclusions, Comparing the CC40
Sources of TI-72 Supplies
Why did TI suspend further HexBus product development and stop selling
the CC40 in late 1984 less than two years after the CC40 introduction in
January 1983? No, it probably wasn't because TI's non release of the "didn't
work very well" Wafertape Digital Tape Drive left the CC40 without any means
of mass storage. TI had that problem solved with the CC40+ which had a built
in reliable cassette interface. But the CC40+ was never released. Why?
A probable answer to these questions is that TI had something better up
its sleeve. In 1985 TI began selling the TI-74, a downsized improved version
of the CC40 with an optional cassette interface. In 1992 these products
are still available.
The TI-74 is "modern" in the sense that TI still actively sells the product
through dealers. Although first released in 1985, my TI-74 user guides have
a 1990 copyright indicating TI's continuing support of the machine. The
TI-74 is a "reincarnation" of the CC40 and 99/4A in the sense that its BASIC
is very similar to TI Extended BASIC for the /4A and almost identical to
the BASIC used in the CC40. Anyone familiar with Extended BASIC on the /4A
will have no trouble programmg the TI-74. The similarities between the
99/4A and the TI-74 are so profound that both the Lima Ohio user group and
the Swedish user group have members who own a TI-74 and DO NOT own a 99/4A.
I have typed in several games and application programs written for the 99/4A
into my TI-74 with very little modification. Finally the TI-74 can be considered
a "pocket" computer because it measures only about 4x8x1 inches. You can
carry the thing around in your shirt pocket if you don't mind having half
the computer sticking out beyond top of the pocket.
The TI-74 can best be described as a reduced sized CC40 with more memory,
a greatly enhanced set of scientific calculator functions, and a slightly
reduced suite BASIC commands compared to the CC40. The keyboard layout of
the TI-74 is very similar to that of the CC40. Anyone familiar with the
key combinations of the CC40 will find the same keys, usually in the same
place on the keyboard, do the same things on the TI-74. Typing FRE(0) on
the TI-74 shows 7710 bytes of program space available for BASIC programs.
On the unenhanced 6K CC40 a FRE(0) shows 5730 bytes available to BASIC.
The TI-74 is powered by 4 AAA batteries or an optional AC transformer.
Most memory contents are preserved when the computer is "OFF". Although
TI makes no clains about how long the batteries should last, my experience
suggests several tens of hours of "ON" time on a single set of batteries
and many more hours of "computer is OFF" time. Unlike many "modern" laptop
and palmtop computers, the TI-74 does not have battery eating features such
as a backlit display screen or a built in hard drive. Like the CC40 the
TI-74 has an LCD display that shows 31 5x7 pixel characters of an 80 character
line. You can scroll or window left/right with arrow keys and can use the
up/down arrow keys to display adjacent lines. A contrast adjustment allows
viewing in most lighting situations.
The keyboard has slightly concave rectangular (chicklet style) keys which
provide a definite tactile response when a keypress is detected. Keys are
arranged in a manner similar to, but not identical with, the CC40 keyboard.
The alphanumeric keys are arranged typewriter style with a large key and
(unlike the CC40) a shift key on BOTH sides of the space bar. Cursor and
other special purpose keys (FN CT Mode Break Run) are lined up in a row above
the letter keys where one usually expects to find number keys. The number
keys form a numeric keypad to the right of the letter keys along with large
ON and OFF keys. Most keys have at least two functions and many have more.
For example, the letter keys all have specific calculator functions in
CALC mode and in BASIC mode these same letter keys can be used to display
on screen most BASIC commands with just two keypresses. Keys are closer
together than on the CC40 so touch typing is not possible. However two finger
typing is fairly easy. I am composing the first draft of this article on
Pressing the MODE key while in BASIC command mode switches the TI-74 to
calculator mode. A total of 70 "scientific calculator" functions are available
by entering a number and then pressing one or two keys to perform some action
on the number. CALC functions include linear regression, permutations,
regular and hyperbolic trig functions, a full range of statistics, and much
more. One interesting CALC function allows you to enter angles in degrees
as degrees-minutes-seconds and have this converted to degrees+decimals.
Factorials up to 83 can be calculated by just entering a whole number and
then pressing the "n!" key. An INV(erse) key will reverse the effect of most
CALC functions. For example pressing INV and TAN will yield the ARCTAN of
the displayed number.
Mathematical display and accuracy are identical to that of the 99/4A
and the CC40. Ten digits are displayed on screen with internal calculations
carried to 13 or 14 digits. Large and very small numbers are displayed in
As an educator, one feature of CALC mode I particularly appreciate is
STAT mode. I can enter a long list of student test scores and then obtain
statistical information such as the median and standard deviation of these
data. Other statistics available once you enter a set of numbers (data)
include sum, sum of squares, number of data entries, regression, line intercept
and slope, and correlation coefficient. Stastical data can be entered as
single data values (as I do for student grades) or paired values (such as
plots on a two dimensional graph).
BASIC programs as well as text assigned to "hot keys" (up to 10 hot keys
each of which will recall from memory up to 80 characters of text and/or
mathematical formulas) remain in memory when in CALC mode and can be immediately
recalled by pressing the MODE button to enter BASIC mode. Stastical data
remain in memory when you switch from CALC to BASIC mode and can later be
accessed by going back to CALC. When you turn the computer "OFF" and later
turn it "ON" you are returned to the mode you left when you pressed "OFF".
Memory contents (BASIC programs, the contents of "hot keys", and stastical
data) are all preserved when the computer is "OFF".
Except for lacking commands for user defined graphics, speech, color,
sprites, and sound, TI-74 BASIC is very similar to TI Extended BASIC on the
99/4A. Keeping in mind the limited screen display of the TI-74, 99/4A users
should have no trouble programming the TI-74. Although TI-74 BASIC has
a few fewer functions than CC40 BASIC the differences between the two are
minor. Most CC40 BASIC software listings can be typed into the TI-74 with
no modifications at all and will run with no problems.
The following functions in CC40 BASIC are not available on the TI-74:
There is no direct access to assembly language except for
- BEEP (Used in the CC40 with DISPLAT AT. There is no sound at all
available on the TI-74).
- ATTACH and RELEASE (A feature of CC40 subprograms I have never actually
actually seen used).
- CALL CHAR (There are no user definable display characters).
- CALL INDIC (No user definable display indicators are available).
- CALL SETLANG (No alternative languages for text prompts. All built
in text prompts in the TI-74 and its software modules are in English).
- CALL VERSION (The version of BASIC is identical on all TI-74's).
- CALL CLEANUP (Instead you can remove from memory variables not
being used in the current program by SAVEing to a non existant device).
- CALL IO on the TI-74. Therefore the following CALL's of
- CC40 BASIC are not available on the TI-74; GETMEM POKE PEEK
- LOAD EXEC RELMEM and DEBUG.
The only important CC40 BASIC software I have that can't be modified
to work with the TI-74 are "DIR" programs designed to read the directories
of mass storage devices such as the Wafertape drive and Quickdisk drive.
These programs are very useful because they give you the exact spelling
of program and data file names. You need the exact spelling to load from
these devices. The directory reading software uses assembly CALL's not available
on the TI-74. The only other important assembly CALL known to me on the
CC40 is a CALL EXEC(xxxx) to deactivate the battery saving automatic power
down. The same thing can be done on the TI-74 by a specific sequence of
Accessories and Peripherals
Standard equipment that comes with the TI-74 includes two book length
guides, a set of alkaline batteries, a plastic hard case, and a quick reference
card that fits into the inside of the hard case's hinged lid. I really like
the hard case and keep my TI-74 in the case most of the time, even when
I am actively using the computer as I am now to enter the text of this article.
The case is very tough and prevents accidental keypresses. The increased
size of the TI-74 plus case does, however, make it more difficult to keep
the computer in one's shirt pocket. If you open the case lid all the way
you can lean the TI-74 against a small object at a convenient viewing/typing
angle and position the case lid over the object's top for stability. Right
now as I type this article I have my TI-74 resting against an apple!
A cartridge port to the right of the display accepts a solid state software
or RAM cartridge. Available software cartridges include LEARN PASCAL, STATISTICS,
CHEMICAL ENGINEERING, FINANCE, and MATHEMATICS. The capabilities of these
software cartridges are almost identical to cartridges of the same name sold
for the CC40 and the TI-95 programmable calculator. When I sent in my TI-74
registration card to TI, I received back a large color brochure describing
TI's custom module service for industry. For about $100 per module TI offers
to manufacture (burn eproms for) custom TI-74 software modules taylored
to a customer's specifications. Specific examples of some custom modules
are described in the brochure.
For me the most useful TI-74 module is the battery backed 8K RAM. A
similar module exists for the CC40. You can save an "image" of the TI-74's
memory into the module, remove the module, and later reinsert the 8K RAM
and load its contents back into the TI-74. Used this way the 8K RAM serves
as a mass storage device. You can also leave the RAM module in the TI-74
and exchange the contents of the computer's memory for what is stored in
the module. You can thus keep two different BASIC programs in the computer
at the same time, one in the RAM module and one in the computer's memory,
switching back and forth between the two. This memory flip-flop trick is
something you can't do with a CC40. You can also use the 8K RAM as additional
CPU memory by invoking CALL ADDMEM. This makes about 15700 bytes of memory
available in BASIC instead of the the TI-74's normal 7710 bytes.
The TI-74 has a 10 pin peripheral connector TI calls the Dock Bus. Available
TI peripherals that fit this connector include an AC adapter adapter (the
"adapter adapter" plugs into the TI-74 and TI's AC9201 AC adapter plugs into
the "adapter adapter"), a battery powered thermal printer, a cassette tape
recorder interface, and an MS-DOS computer interface. I don't yet own any
of these peripherals, so the descriptions below are based on information
published by TI and on articles that have appeared in past issues of TI PCC
The PC-324 THERMAL PRINTER is set up as device #12 and uses an unusual
size thermal paper roll. You can either purchase FAX paper and cut it to
size with a hacksaw or pay $5 at a dealer for a 3 roll pack of "official"
paper. Sort of reminds you of the paper "problem" with the 99/4's Thermal
Printer (TP)! The small PC-324 printer is about the same length and width
as the TI-74. It runs on batteries or an optional AC adapter. Text is
only 24 columns. There is only one text font and there are no dot addressable
graphics. From CALC mode you can use the PRINT key at any time to print
the screen display. From BASIC mode you can LIST programs or OPEN the printer
in a program or from command mode and print whatever you want.
The CI-7 CASSETTE INTERFACE CABLE allows you to use most cassette audio
recorders, even those that use mineature cassettes, to save BASIC programs
or data files to tape. It appears to work the same way as the cassette interface
of the never released CC40 PLUS. Its operation also resembles that of the
Wafertape drive. You can save several files sequentially on the same tape
each with a different file name. If you don't know the exact starting position
of a particular file the TI-74 can search the tape from the beginning for
a particular file name and when found load that file. The TI-74 can also
be programmed to load the next file found on the tape irrespective of file
name. Screen prompts are available telling the operator to press the recorder's
PLAY, RECORD, and STOP buttons and the computer automatically senses the
beginning and end of the requested file. You cannot use the CI-7 to save
programs from a CC40. Many have tried and failed to do this. Apparently
the TI-74 contains within it specific code needed to operate the CI-7 cassette
interface, code which is lacking in the CC40.
The PC INTERFACE CABLE connects between the Dock Bus and the 25 pin parallel
port of an MS-DOS computer. With this cable you can use the TI-74 to directly
control the MS-DOS computer via several device numbers. Addressing device
14 lets you print using a parallel printer connected to the PC. Device 45
lets you direct output from the TI-74 to the PC's monitor for a nice 80 column
multi line display. You can save or load TI-74 programs to and from the
PC's disk drives by referencing device 100. Text in ASCII format can be
saved to the PC's drives with device 101. If you own an MS-DOS computer this
cable would seem to be a very useful TI-74 peripheral. Can it be used with
the CC40? I don't know, but someone should find out. The PC interface may
be the mass storage solution for CC40 owners who cannot get obtain a Quickdisk
or Wafertape drive.
Superficially the 10 pin Dock Bus looks quite different from the 8 pin
HexBus. However, as first noted in 1990 in articles published in TI PCC
NOTES and later in an article by Dan Eicher in the March 1992 issue of the
Lima User Group newsletter, the Dock Bus and HexBus are electronically identical.
Two extra Dock Bus lines not found in the HexBus that allow an external
6 volt source to power the computer or peripheral through the bus. By connecting
the proper wires of a HexBus cable to corresponding wires of a Dock Bus cable
ALL HEXBUS PERIPHERALS ARE COMPATIBLE WITH THE TI-74! If you don't want
to make your own cable you can buy one from L.L. Conner for $15. Plug one
end of the Conner cable into the TI-74's Dock Bus and attach a HexBus cable
to the other end. With this HexBus/Dock Bus cable I have used my TI-74
with the following HexBus peripherals: RS232, Printer 80, Printer Plotter,
Wafertape Drive, and Quickdisk drive.
I much prefer to my use Printer 80 with my TI-74 rather than the 24 column
PC324 printer. Like the PC324 the Printer 80 can be run on batteries or
an AC adapter. Unlike the small hard to find expensive rolls of thermal paper
used by the PC324, the Printer 80 uses easily obtainable FAX paper rolls
or with a Thermal Ribbon obtainable from Sears or by mail from TI regular
sheets of typing paper.
Mass Storage and CC40/TI74 Software
With my TI-74 I can OLD SAVE and OPEN files to and from my Quickdisk
(device 8) with no problems at all. This is in spite of the fact that I
have the HexBus rather than the Dock Bus version of the Quickdisk drive.
All I need is the HexBus/Dock Bus interface cable made by L.L. Conner.
I know of someone who uses a Dock Bus Quickdisk drive with his CC40 also
with no problems. The few CC40 applications written for the Wafertape drive
assume this device is configured as device #1. That's how I have always
used my Wafertape Drive with my own CC40. It is fortunate that the tape
drive can be switched to other device numbers because I can't successfully
use my Wafertape drive as device 1 with the TI-74. The TI-74 expects the
CI-7 cassette interface to be device 1. If I switch my Wafertape drive to
some other device number (I use device 2) then I can OLD SAVE and OPEN files
to and from wafertapes with my TI-74.
I knew when I bought my TI-74 that the syntax of TI-74 BASIC is almost
identical to that of CC40 BASIC. I now know that the similarities between
the BASICs of these two devices are more profound. Any BASIC program written
on a CC40 and saved to Quickdisk or Wafertape will successfully OLD into
the TI-74 and if the program doesn't use any of the BASIC functions unique
to the CC40 will RUN in the TI-74. Almost my entire library of CC40 BASIC
programs stored on disk or wafertape will load RUN out of my TI-74! The two
computers use similar 8 bit central processor chips (TMS70C20 for the CC40
and TMS70C46 for the TI-74) that use the same assembly instruction sets and
BASIC token codes.
General Conclusions, Comparing the CC40
The only reason for using for using small "notebook" or "palmtop" computers
such as the CC40 or TI-74 is portability and/or ease of operation. The additional
memory and better displays of desktop computers mean that in general desktops
are more powerful. Software is available for desktops that can accomplish
anything that can be done with ROM cartridge or BASIC software available
for the CC40 and TI-74. There is a lot to be said for portability! The ability
to carry the CC40 or TI-74 around with you and use them anywhere (a classroom
the office on a camping trip etc) is the raison d'etre of these small computers.
Unlike "modern" laptop computers whose batteries usually last less than
4 hours per charge these small TI machines last tens or a couple of hundred
hours of on time on a set of batteries. For use in the field the TI-74
and CC40 and their battery operated peripherals offer lots of convenience.
For example, I am typing this article while I lay in bed proped against
a couple of pillows. A few minutes ago I made a phone call from the phone
by my bed that required me to look up the phone number. I have my name/address/phone
data base stored in my TI-74's 8K RAM cartridge, so I did a CALL GET(-1)
to store this article in the RAM cartridge and at the same time put my data
base in the TI-74's memory. I looked up the number and made the call. Then
I did another CALL GET(-1) to bring back my document into memory and put
my data base back into the RAM cartridge.
Advantages of the CC40
- Its CHEAPER. You can get one used for $55. Used TI-74s are hard
to find and a new one costs $100.
- CC40 BASIC is a bit more powerful.
- The KEYBOARD is physically larger and thus according to some people
easier to type on than the keyboard of the TI-74.
- There is an assembly language word processing cartridge called
MEMO PROCESSOR available from TI for the CC40. No commercial word processing
software is available for the TI-74. I am using a BASIC word processor program
I wrote myself to enter this article into my TI-74. MEMO PROCESSOR is much
better than my BASIC word processor.
Advantages of the TI-74
- CALC MODE. Scientists, engineers, and educators will appreciate
the rapid availability of 70 scientific and statistical functions on the
TI-74. The same sorts of calculations can be done in BASIC with the CC40
(and the TI-74) by putting formulas into BASIC programs, but doing the math
directly from the keyboard is much easier and faster.
- More user memory is available on the TI-74 than you get in an unexpanded
- Physical size. The CC40 is just a little too big to get your hand
around and is slightly awkward to carry around or hold in one hand. No matter
how you carry the CC40 it seems the keyboard overlays are about to fall
off and your gripping fingers have trouble finding a place where they don't
press some keys. In my opinion the TI-74 is much easier to handle. You
can easily and grasp the TI-74 with the fingers of one hand. The hard case
prevents dust accumulation, accidental keypresses, and the accidental loss
of the quick reference card (or the LEARN PASCAL keyboard overlay). I feel
very comfortable about carrying my TI-74 around with me in my hand, in my
briefcase, or in my coat or shirt pocket just about everywhere I go. Personally
I have no more difficulty typing on the TI-74 keyboard than I do on the CC40.
In both cases two finger "must keep looking at the keyboard" is my technique.
Touch typing is not really possible on either machine.
- The DOCK BUS is physically superior to the HexBus. Although the
two bus designs are electronically identical the HexBus is structurally
flimsy. When inserting a HexBus I/O cable into the bus on a CC40 or HexBus
peripheral it is hard to seat the cable properly. There is lots of "play"
in the HexBus opening and it is possible to bend some pins in the bus as
you fool around with inserting the I/O cable. The HexBus cables themselves
are flimsy. They are very flexible and it is difficult to avoid pulling
on the cable rather than the small rigid cable end piece when removing an
I/O cable from the HexBus. The DockBus and its I/O cables are more substantial.
Cables fit snugly into the bus with no free play and little likelyhood of
bending a bus pin. The cables are stiffer than HexBus cables and have large
easy to grasp ends. Physically the DockBus and its cables seem more substantial
and thus probably more reliable than the HexBus.
The capabilities of the CC40 and TI-74 are similar. The TI-74 is a better
math calculator. The CC40 has a better word processor but both can be used
as calculators or text processors. Because of the memory flip-flop capability
of the 8K RAM and for physical reasons I prefer the TI-74.
Sources of TI-72 Supplies
Available by credit card directly from TI at 806-747-1882:
- HX1010 Printer 80, the 80 column HexBus printer, $70
- CI-7 Cassette interface $35
- PC324 Thermal printer $60
- Technical manual $5
- 8K constant RAM cartridge $50
- Learn Pascal, Stastics, Mathematics, Finance, Chemical Engineering
software cartridges $50 each
- TP324 thermal paper and PC Interface cable also probably available
directly from TI, prices unknown.
Available from EDUCALC at 800-677-7001 or (credit card orders only
24 hours) 800-535-9650
- TI-74 (the topic of this article) $99.95
- Statistics, chemical engineering, finance cartridges $39.95
- 8K constant RAM cartridge $39.95
- PC324 Thermal printer $89.95
- TP324 paper for printer $4.95
- CI-7 Cassette interface $26.95
- PA201 AC interface for TI74 (the "adaptor adaptor", uses adaptor
- AC9201 adaptor to power printer and/or TI94 $16.95
- PC interface cable, allows storage of TI74 software on PC disks
and use of PC screen controlled by TI74 $54.95
Available from L.L. Conner Enterprise 1521 Ferry St. LaFayette IN 47904,
- Custom cable to connect HexBus peripherals to the TI-74s DockBus,
a special order item, $20
- Custom cable to connect HexBus RS232 to TI99/4A RS232 card, a special
order item, $20.
- Various HexBus peripherals. Call for availability.
Available from T.A.P.E. 1439 Solano Place, Ontario California 91764,
- Quickdisk disk drives, either the DockBus version or the HexBus
version (with the L.L.^Conner cable) will work with the TI-74.
Jim Lesher, 722 Huntley, Dallas Texas 75214, phone 214-821-9274
- Nice selection of HexBus peripherals