The only time I've seen it go over 64 was when stepping through the T-Word code 
and watching the buffer byte while sending a track (128 bytes + header) from 
sardine.But I may have been watching the wrong byte in memory.
As far as the 64 byte limit, I had a heck of a time getting that to work 
properly with the Android device. With Windows, the XON/XOFF works pretty well. 
I ended up sending 8 byte chunks and then checking for a flow control byte. A 
pain, but I think I have the timing right.

    On Monday, October 17, 2016 2:16 PM, Mike Stein <> wrote:

 Looks like John beat me to it ;-) Steve played with expanding the buffer a 
long time ago while we were playing with the M100-on-the-Internet but never got 
it working 100% reliably, so we ended up handling XON/XOFF in the bridge 
hard/software instead which could respond instantly. m
 ----- Original Message -----  From: John R. Hogerhuis  To: Model 100 
Discussion  Sent: Monday, October 17, 2016 5:05 PM Subject: Re: [M100] mComm 
 On Mon, Oct 17, 2016 at 1:11 PM, Kurt McCullum <> wrote:
      John, Thanks for info. Is that a TELCOM limit? The reason I ask is 
because when running virtual T with TS-DOS, I notice that the buffer can go to 
255. Or at least the byte which holds the buffer size. 

 In my experience I've found that all 8-bit bytes go to 2^8 - 1 = 255 
 Just teasing :-) It could but it should never in practice have a value > 64. 
Have you observed a higher value than 64? 
 It's not a limitation of TELCOM per se, it's a limitation of the receive 
interrupt handler logic and the size of the circular queue-on-array reserved 
for receiving bytes. The same receive handler is used for TELCOM and BASIC 
access to the serial port. 
 See Page 186 
 It shows a receive buffer of 64 bytes. If it went beyond the bounds, unmasked, 
I would expect it to corrupt other data structures. 
 The high-water mark for the buffer is 40 (the point at which the receive 
handler sends XOFF), which probably makes more sense in the context of a 64 
byte buffer than a 255 byte buffer :-) 
 -- John.


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