The engine probe answered two questions on the air, and they point opposite
ways.
TxBufLen is the number of characters left to transmit. Seventeen characters
pushed, five decoded back, and it read 12, counting down to 0 as the message
went out. So the pump no longer counts character times off the clock: it asks
the engine, feeds while the answer is under Lead, and asks again. The baud rate
is now only the fallback for an engine that will not answer.
A backspace is not an edit. Pushed in as a character it made the count go up by
four and the text went out unchanged, so text the engine has been given cannot
be taken back, only aborted. EngineTypeAhead was built on the opposite belief
and is gone, along with the setting that chose it and the interface that existed
to switch between the two.
A count that stops going down means the engine is holding what it has: MMTTY set
to Word out keeps a word until the space after it. The pump feeds one character
per look while that lasts, so the space arrives and the word goes out rather
than the message sitting there.
The probe kept two bugs of its own that this run showed: it read the count a
millisecond after pushing, saw 0 and called the message finished, and it started
a step while the previous unkey was still in flight, so that step ran with the
engine down. It now needs two empty answers in a row and waits for the engine to
say it has stopped. It also asks what {RX} does to a word the engine is holding,
which decides whether a macro without a trailing space loses its last word.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RtspmWmS7f8kUvcyaHpRWZ
Nothing was ever transmitted. SetMmttyPTT does not start a transmission: N1MM
calls it with 1 to stop once the buffer is empty, which is its XmitOff, and with
0 to stop now, which is its AbortXmit. A transmission starts by setting the
control's PTT property, in XmitOn.
So the bridge learns `key <0|1>` for that property, and MmttyEngine now keys
with it, ends a message with SetMmttyPTT(1) so the buffer still goes out, and
aborts with SetMmttyPTT(0). This is the digital {TX} in the entry window and the
digital window as well as the probe: none of them could key the engine before.
The probe checks that the engine keys before it measures anything, and stops
with a plain statement if it does not, rather than reporting numbers from an
engine sitting still. It also asks a new question: whether the engine holds a
word until the space after it, which is MMTTY's Way to send. Received characters
are marked as noise while the engine is not transmitting, since a machine with a
sound card decodes the band all the way through the run.
The first run on a real engine says MMTTY 1.70 connects, the control answers
TxBufLen and refuses NotAProperty with DISP_E_UNKNOWNNAME. What TxBufLen counts
is still open: read while nothing was transmitting it rose over time and rose by
four after four backspaces, which is not what characters-left would do.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RtspmWmS7f8kUvcyaHpRWZ
MMTTY has a type-ahead buffer of its own: characters go into it, a backspace
takes back one it has not transmitted, and TxBufLen says how many are left. Used
that way it paces itself, so there is no gap between characters to tune and no
baud rate to keep in step with the engine.
EngineTypeAhead does that, and Config > Digital picks between it and the pump
that is there now. Off is still the default: three things it rests on have never
been seen with a real engine.
tools/Nonemm.EngineProbe asks the engine those three questions and writes the
answers to a file. It starts MMTTY through the bridge, pushes a message, polls
TxBufLen while it goes out, backspaces over text that has and has not been
transmitted, and logs what came back on the receive side and when.
The bridge learns one verb for it: `buffer` reads TxBufLen and answers with the
count, or -1 when the control will not say. A property the control does not know
is a log line rather than an error, since it stops nothing.
TypeAhead and EngineTypeAhead share the TransmitBuffer interface, which is what
the digital window now works through, so the window does not know which one it
has.
docs/unfinished.md states what each buffer assumes and how to run the probe.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RtspmWmS7f8kUvcyaHpRWZ
