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Can I load Model I/III cassettes on the Tandy 200?

K

KG7PFS

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Aug 2, 2016
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Cave Junction, Oregon
The TRS-80 Model 4 is compatible with the Model III in Model III mode. The Model III is mostly (?) compatible with the I, so all that Model I/III software I find at yard sales, flea markets, thrift shops and sometimes even eBay (not that there's any on eBay now, so don't bother looking) should work on my model 4.

The trouble is, mine is a 4P, with no cassette port. No one ever even sold a cassette option (did they?). So while getting old disk software to work is no problem, I can't use all those Model I tapes...can I?

The 100, 102 and 200 have a cassette port and a serial port. While I/III software won't run on a 200 unless it's written entirely in BASIC (some of it was!) I should be able to load the file from tape and send it to the 4P *if* the 200 can read the old I/III tapes, and *if* a better programmer than me can tell it what to do with what it loads. Has this been done?
 
The Model 1's Tape speed was 500 Baud. The Model 3 (&4) used L (LOW=500) and H (HIGH=1500) Baud.
The Basic programs are saved in a TOKENIZED format, but can be saved as ASCII by using the ,A appended
to the SAVE command. The ASCII saved programs load the same as the tokenized format, but are somewhat
larger and take up more Memory when loaded.

I'm not familiar with the Model 200, but you should be able to get a lot of the basic programs to work if the
display is located at 0x3000 as the Model 1 and 3.

Programs and Games saved as Machine code likely won't run. They are saved on Tape with three address's.
Starting Load Address (in hex), Ending Address (in Hex) and Jump to Address (Hex Address of Start of Program).
Example Start = 0x5000 Example End = 0x6500 Example Jump to Address = 0x5100

Programs like TASMON and HTASMON (Loaded HIGH in RAM) can accept the Tape's HEX BYTES and get
you the three needed address's. From there you can write a small program that takes the START, END, and
JUMP TO address's and move them High and save that program to Floppy Disk. Now you write a Loader
and add it to the Program on Disk to Load it back LOW and Execute it. Now you don't need to save the
Tape as the Machine Code is on Several Floppy's. But, they are still unlikely to run on the Model 200.

You could Run an Emulator of the Model 1, 3 or 4 and load the Cassette Software. There are lots of the
Cassette Software on the Humongous CP/M Archive saved as a .CAS files. Once you have the software
on an Emulator, you can get it to the Model 4P by Floppy or Serial Transfer. Getting it to the Model 200
will still be a problem.

This information could be in error as my memory isn't what it used to be, and I don't remember exactly
what I did with my Model 1 40+ years ago.


Larry
 
I might have to use an emulator. I hope not. I wouldn't know what to do with an emulator if I had one. I can probably download most of this software and transfer it by serial port, but using only classic hardware is more fun. I have no intention of trying to run most model I/III software on the 200, only using the 200 to transfer it. It sounds like it would be easier to build a cassettte interface for the 4P, though.

Where is this Humongous CP/M Archive?
 
There are basically two sections, with a dump truck load in each section.
http://www.classiccmp.org/cpmarchives/

and the TRS-80 section.
http://www.classiccmp.org/cpmarchives/trs80.php

I searched and searched for my directory listings and haven't located all the .CAS files.
I likely have them bookmarked on my old laptop. Will have to export the list and search it
to know for sure. I'll run across it at some point in my searches.

Larry
 
ldkraemer said:
I'm not familiar with the Model 200, but you should be able to get a lot of the basic programs to work if the
display is located at 0x3000 as the Model 1 and 3.



Larry
Click to expand...

It happens that I was sitting here reading this post with the Model 100 handbook open beside me. Appendix C gives information about "Transferring Data Between the Model 100 and the Model II". I do not have a Model I, II, III or 4 (yet) but I do have a Model 100 and a Model 102. While I can't verify the technique, therefore, apparently it is possible.

I have scanned Appendix C and am attaching the OCR to this message..

-CH-

Appendix C / Sample Sessions


Transfering Data Between the Model 100
and the Model II

You may transfer data between the Model 100 and the Model II using the Terminal program on
the Model II and the TELCOM program on the Model 100. Model 100 programs must be stored
in ASCII format (files with a .DO extension — either Text files or else BASIC program files
SAVEd with the A option.)
First, make the preliminary hardware and software connections by following these steps:
1. Connect the two computers via an RS-232C Cable (26-4403) and a Null Modem Adapter
(26-1496). See Figure A-4 in Appendix A.
2. Insert a TRSDOS System Diskette which contains the TERMINAL Program into the
Model II. (All standard TRSDOS 2.0 System Diskettes contain the program).
3. Initialize the drive by typing:
(ENTER
and then initialize the RS-232C port by typing:
SETCOM A= ( 4130 0 te tE ) (ENTER)
You may use other SETCOM parameters for the Model II as long as the Model 100 can
match them. The settings used in this example allow the fastest data transfer.
4. Now enter the Model II TERMINAL program by typing:

TERMINAL (ENTER)

5. On the Model 100, move the Menu Cursor to the word TELCOM and press (ENTER). The
TELCOM prompt will appear. Press STAT ((F3)) and type:
7 8E1E ENTER
This sets the Model 100 communication parameters to match the parameters you previously
set on the Model II.
6. Enter the Model 100 Terminal Mode by pressing TERM ((F4)).
Now that the Computers are connected and have matching communication parameters, you may
transmit files to and from the two machines.


Downloading File from the Model II to the Model 100
To download a Model II file to the Model 100, follow these steps:
1. On the Model 100, press DOWN ((F2)). TELCOM will prompt you for a file name. Enter the
name of the new file, using the .D0 extension (TELCOM will add this extension if you don't
supply it), then press ENTER). The label Down will appear in reverse video.


2. On the Model II, type G (ENTER) (for get disk file), and enter the filespec of the file to be
transferred to the Model 100.
3. Once the file is in RAM, type X (ENTER) on the Model II to transmit the file. As the file goes
to the Model 100, TELCOM displays the information being transfered on the Model 100
Screen.
4. When all of the data has been transmitted. press ED on the Model 100 to exit the Terminal
Mode. When prompted Disconnect?, press CD (ENTER).

5. Press (BREAK) on the Model II to return to the TERMINAL Menu. Then type Q ENTER to exit
the TERMINAL program.
The Model II file is now stored in the Model 100's memory under the file name you specified.


Uploading Model 100 Text Files to a Model II
To transmit a Model 100 file to a Model II, follow these steps:
1. Enter the TERMINAL Program on the Model II by typing T (ENTER
2. On the Model 100, press UPLOAD (n).
3. TELCOM prompts you for the name of the file to be uploaded. Type the file name

(remember that it must have the .DO extension!) and press
(ENTER
4. TELCOM will then prompt you for width. This refers to the maximum number of characters
transmitted before transmitting a carriage return. Enter an appropriate value, then press
(ENTER) . Remember that the Display on the Model 100 is 40 characters wide.
If you want to send the file "as is," simply press
ENTER)
5. As the file is transferred, the Up label appears in reverse video, and the transmitted data
appears on the Model II Screen.
6. When the transmission is complete, the Up label returns to normal video.
On the Model II, press (BREAK) to return to the TERMINAL menu. Now press C (ENTER) to
save the RAM buffer to a disk file. TERMINAL prompts you for the file name. Enter any
valid file name. To exit from the TERMINAL program on the Model II, type Q (ENTER).
7. To exit the TELCOM program on the Model 100, press F8 to exit the Terminal Mode.
When prompted Disconnect ?, press (Y) (ENTER). Now press F8 again to return to the
Main Menu.
The Model 100 file is now stored on your Model II disk, under the specified file name. The new
file will have a Record Length of 1.
 
KG7PFS said:
The 100, 102 and 200 have a cassette port and a serial port. While I/III software won't run on a 200 unless it's written entirely in BASIC (some of it was!) I should be able to load the file from tape and send it to the 4P *if* the 200 can read the old I/III tapes, and *if* a better programmer than me can tell it what to do with what it loads. Has this been done?
Click to expand...

The Model 100 line uses a cassette format with a line encoding that is identical to the Model III/4 high-speed, 1500 baud, wave-based (i.e. zero-crossing-detector-based) encoding. However, the Model I tape formats are pulse-based. The Model III and 4 include hardware for reading those old pulse formats as well as hardware for detecting the zero-crossings in the new format. The Model 100 does not include that extra hardware for reading the old formats.

So, your Model 200 can't be used to read Model I 500-baud tapes, but it could be used to read any tapes in the Model III 1500-baud format. The "better programmer" wouldn't even need to write any low-level tape I/O routines. The documented ROM routines CTON, SYNCR, CASIN, and CTOFF would suffice. See the Model 100 Technical Reference Manual, p. 87-88 for the interface to those routines. For a description of how those routines work, see "Inside the TRS-80 Model 100", chapter 12.

"Has this been done?". I would guess not.
 
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