*BL (Buffer Limit Command)
I've been trying to understand what I may be able to do with the *BL command with a Geneve 9640 computer.

Tim Tesch has a program called PORT that works well all the way up to 38400 on file transfers so I know it can be done.  Myself, i am working on a different terminal emulator and I am getting a strange and reproducible response when doing Xmodem (128 byte) downloads.

I have not figured out what, but I can start a download at 38400 baud and the moment the 128 block reaches a transfer of 10,112 bytes, I error out.

I have experimented with the video display as it updates the bytes transferred, so I know the routine when it goes from a 4 character display to a 5 character display of bytes transferred, is one issue.  I am right on the cusp of the CPU speed with too many cpu cycles away from capturing RS232 data.  When I comment out the display of bytes transferred, it continues on past 10,112 until some other point when it then errors out.

At first, I thought it may have been tied to interrupts or the handshaking, but there may be something happening I am not fully comprehending.  When I change the buffer limit with a AT*BL64, I do not even get the first block.  If I go to the higher end of the limit, I get some other responses.

So, what I am wondering is what is the WiModem232 doing with a smaller buffer versus a larger buffer between a BBS (Mystic BBS software) back to the modem from where it then connects to my software and computer.  I hope that is explained well enough.

Could there be a preferred or optimum BL setting for packet size with the file transfers.  

Please note, it has been years since I have done any significant programming, and I am still pretty green at coding for an RS232 interface.  However I saw some subtle differences if I varied the BL setting when I thought any changes to that setting should have had no impact on the file transfer.

Any insight would be appreciated.


Messages In This Thread
*BL (Buffer Limit Command) - by Beery Miller - 02-20-2018, 08:20 AM
RE: *BL (Buffer Limit Command) - by admin - 02-20-2018, 09:02 AM
RE: *BL (Buffer Limit Command) - by Beery Miller - 02-20-2018, 09:11 AM

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