Rob's Ramblings

Tuesday 16 July 2013

Retrochallenge 2013

In a fit of madness, I decided to re-enter this years competition.

If you cast your mind back, I entered last time with the intention of sorting out my "man cave" as the attic was described, in order to get the viewdata BBS back up and running.

Unfortunately, building work interrupted matters, and I didn't get very far.   More unfortunately, the building work stalled, and I still don't have a safe floor up there, so pretty much everything is still in boxes.  A year on.  The tale of what happened and what went wrong is going to make a great story at some point, but not yet.

So, this year, I've been hoping to get something working under emulation.  The ideal would be an emulated modem that can answer VoIP phone calls, and pass the user to an emulated server of some sort.  Modems and VoIP are reckoned not to work very well, but that's the "modern" types. V23 has no problem at all, as I proved when using the real stuff over it.

The trick is going to get a software modem working at such a slow speed!  IAXmodem uses SpanDSP, which proports to support the old FSK modems, including V23, but I've not yet managed to get it working.  Part of the issue is that the whole thing is geared up for faxing, so assumes some level of intelligence from the far end.  V23 modems, particularly the 25 year old ones, don't do anything intelligent!

So, that's the task this month.  Getting iaxmodem (initially) to answer a call from an ancient terminal.  Then I'll hook it up to a BBC micro emulator and run the BBS entirely virtually.

I'm acutely concious that over half the month is over, and I've not done anything yet!

Long term goal is to find a backup of the original Prestel software and databases, run up a GEC mini-computer emulator, and actually run the real thing.  But so far that's been elusive.  Anybody know of any surviving discs or tapes from Prestel itself?

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