Date   : Tue, 18 Sep 2018 20:38:40 +0100
From   : robert@... (Rob)
Subject: Announce: Brandy Basic - with teletext?!

LOL.

Well that page I attached is from official documentation  - specifically
the Prestel Bulk Update Technical Specification, April 1985 - if it helps
:-)

The only other control codes you might be expected to deal with is ENQ -
this is sent at the start of a connection and would trigger a "real"
Prestel terminal to immediately transmit it's ten digit ID.  There is also
a sequence that the Prestel computer could send that would store the ID
within a set's memory (goto page 924 to do this) but I've not yet found
details on that one.  For most microcomputer clients, such as I used at the
time, this was handled through off-line mechanisms, if at all!

(As a side-note, many Bulletin Board Systems also used ENQ at the start to
trigger a caller's software to automatically fill in their name/password.
As a BBS operator, I fairly often found Prestel ID numbers, and
occasionally ID+PW, in my logs...)

Rob


On 18 September 2018@..., Michael McConnell <soruk@...>
wrote:

> Thank you for that.
>
> Not yet pushed to fit, but my code no longer does VDU 8,32,8 when 8 is
> received. Telstar seems to accept 8 (but not 127) as a delete when keyed,
> so for now, when I key either Backspace (8) or Delete (127), it sends 8 and
> locally does a VDU 8,32 then the received 8 will complete the backspace.
> But a received 8 by itself won't now erase the character under the cursor.
>
> In case it isn't painfully obvious, I wrote this client without ever
> seeing a spec, and it's all trial and error (with the occasional packet
> trace). It's a miracle it works at all.
>
>
> On September 18, 2018 4:02:17 PM GMT+01:00, Rob <robert@...>
> wrote:
>>
>> You can send character 127 to the host, which *might* be interpreted as a
>> delete, depending on the host software.  (The terminal on my desk at the
>> moment sends that when you press the "correction" key up at the top; there
>> is no actual backspace or delete key!)  .  But you will receive back left,
>> space, left.  So from the point of view of coding up a temrinal emulator,
>> you just have to deal with a cursor-left sequence.  (which can be received
>> outside of a delete sequence, too.)
>>
>> Rob.
>>
>>
>>
>> On 18 September 2018@..., Michael McConnell <soruk@...>
>> wrote:
>>
>>> So, when you want to key a delete, what code is sent and what is the
>>> expected behaviour?
>>>
>>> On 18/09/18 15:46, Rob wrote:
>>>
>>>> If you are talking viewdata, character 8 is simply cursor left.
>>>> character 127 will display a square block.  There is no actual delete
>>>> sequence specified.
>>>>
>>>> Rob
>>>>
>>>>
>>>> On 18 September 2018@..., Michael McConnell <soruk@...
>>>> <mailto:soruk@...>> wrote:
>>>>
>>>>     On 18/09/18 12:41, Michael McConnell wrote:
>>>>     > On 18/09/18 12:38, gARetH baBB wrote:
>>>>     >> On Fri, 14 Sep 2018, Michael McConnell wrote:
>>>>     >>
>>>>     >>>    410WHEN 8: IF POS=0 AND VPOS=0 THEN VDU31,39,23 ELSE VDU 8,32,8
>>>>     >>
>>>>     >> VDU 8,32,8
>>>>     >>
>>>>     >> is very wrong though.
>>>>     >     > Without that, hitting Backspace to delete doesn't delete
properly.
>>>>     > Unless when you delete it's supposed to leave behind what you
deleted on
>>>>     > screen.
>>>>
>>>>     Actually - I can make it just VDU 8 there, and do a VDU8,32 if 8 or 127
>>>>     is received at the keyboard - and it seems to behave itself. Does that
>>>>     also break the spec?
>>>>
>>>>     -- Michael
>>>>
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>>>>     bbc-micro@... <mailto:bbc-micro@...>
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>>>>
>>>>
>>>>
>>>
>>
> --
> Sent from my Android device with K-9 Mail. Please excuse my brevity.
>