It stems from Enterprise's ANSI-spec BASIC where the programmer has to be able to specify the channel number

Interesting, so designing EXOS was also affected by the to-be-written IS-BASIC for EXOS? Or were they parallel projects, and one of the "main users" of EXOS would be IS-BASIC from the very first moment of software development for EP? I had the idea that first EXOS was designed, created as a multi-purpose OS, and then only IS-BASIC is written.

Oops sorry to hijack this discussion, now back to SymbOS...

I moved it to the right topic

Bruce! I hope you are enjoyed the visit in Hungary and the party!

In the party you asked something about the TVC BASIC version. Can you remember what is your question?
The TVC what you see are the first model (TVC 32K) with BASIC version 1.2

And question from Tuby128: is any easter egg in the TVC like the "SET STATUS 42" on the EP?

Can it be, that the set status 42 is not your work. There is a lot of monogram, maybe it was made by an another developer.

I noticed the version is only 1.2. Videoton had the source code and I was wondering how much they had changed it over years. Answer: not much if it is only 1.2! (I cannot remember what version we delivered but it would have been 1.0, 1.1 or 1.2.)

For the next party I will bring the 64K+ version which has a 2.2 version
TVC 32K and 64K were sold with version 1.2
We also have a ROM image of 1.1 and 2.1 versions, probably these from prerelease machines.

The book of the 64K+ tells about the BASIC versions:
Version 1.3: some bugs of 1.2 were fixed:
- at string comparision the length byte is not compared (in 1.2 space needed to be added for the shorter string)
- at INPUT the maximum string length is now really 254 chars (previously only max 251 worked)
- using user defined functions in PRINT USING does not cause any more errors
- ELSE <number> type instructions do not make stack garbage anymore
- fixed the problem when pressed more than two keys make a wrong characters
- video driver now rounding the coordinates instead of truncating
- new PROGID system variable, it is used by VTDOS for check BASIC is running when the DOS called?
- character set compressed: characters under 80h use only 9 rows of 10. Now only 9 rows stored in the ROM, and the video driver adds the plus empty row

BASIC 2.0 includes everything from 1.3, and two more bug fixes:
- PRINT USING now with rounding values
- SOUND doesn't destroy the EXT5 and EXT6 vectors

New commands:
- AUTO
- RENUMBER
- FKEY, for this also add function keys function to the OS. The TVC has no fkeys, LOCK+number can be used as function keys
- ON EXCEPTION GOTO
- EXCEPTION

New functions:
- ERRNUM
- ERRLIN
- HEX$
- DEC

Extended commands:
- CONTINUE, now can be used in program for exception handling (like in the IS-BASIC)
- PLOT:
  - relative coordinates with +/- sign
  - RECTANGLE, for this added function to the video driver
  - POLYGON, for this added function to the video driver
  - ELLIPSE, for this added function to the video driver

BASIC now has expansion capability.

Most of them already existed in the IS-BASIC 2.x (the RECTANGLE and POLYGON are missing )

I'm sure, the 2.0 are from you, Bruce!
Especially because there is an English document about these

Question about the TVC from Gflorez: Made for the Hungarian market, why the error mesages of the TVC are in English?
It is ok Bruce, you don't speak Hungarian But the Videoton never wanted it "please put these translated messages"?
And the Videoton don't got the sources, then can't do the own translations?

In some early articles about EP in old magazines I saw that journalists writes about IS-Basic sound commands "SPLAT" and "BOOM".

Are you into graphics? The Enterprise has a hi-res mode of 672 by 512 screen dots, more than twice the resolution of an Atari or Commodore 64. Like the Atari, the Enterprise has 256 colors, but unlike the Atari, all 256 colors can be displayed at once. And the BASIC includes graphics commands like PLOT, CIRCLE, PAINT, DESK, PAPER, INK, and PALETTE – plus turtle graphics. There are sound commands like PITCH, PLAY, TUNE, RELEASE, BEEP, BOOM, and SPLAT. And how about these examples of fascinating BASIC commands: CAUSE EXCEPTION, CHAIN, HELP, IMAGE, LOOP, MERGE, TOGGLE, TRACE, FKEY, TAPE SOUND, CHARSET FROM, CAPTURE, ECHO, XOR, TRUNCATE, and ZAP.

Ainsi un effet de stéréo sera réalisable, à condition de connecter l'Élan à une chaîne hifi. Bien sûr l'enveloppe du son peut être contrôlée en Basic à l'aide d'un macro-langage. Pour la sonorisation de logiciels ludiques vous disposerez de commandes préprogrammées tels que « Splat » et « Boom ».

Theese commands was deleted from final product?