Thanks for the great info. Binary, ya when i send say an XOFF it would just be part of the data stream and one of the data stream may well be a protocol byte. Guess i will try to do a hardware protocol, just the more i learn the less promising it looks. The stuff i have seen so far indicates that those handshake lines are not "supposed" to control data flow, but rather only device status. The other approach is like elric said, just send a header string to the PC program "I'm gonna send 10240 bytes now!", or "Please send me 10240 bytes now!". And use NO protocol. Just slow it down till it works. Sorry, i've been thinking aloud, Thanks again for the ideas.

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To answer your original question, one uses the MODE command to set up speed, bits etc., and the port uses the cable connections for handshaking with DTR and RTS/CTS although these can be bypassed by the wiring connections if required. Use the P (I think) parameter on the end of the mode command, otherwise data may be lost. Good luck - Keep us posted.

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Mike Newcomb, If that is true then i should not be worrying about setting up protocol. I can just use HW protocol. Man i am pulling my hair out trying to understand the protocol. Transmitter protocol: Two options: Host or Terminal Reciever protocol: only seems to have one option, but who controls transmission backwards ? ALL soft i found has option "software protocol" but there are four of those and they won't tell what they are using. "hardware protocol" has the same confusion, they will never tell what HW protocol they are using: CTS/RTS, DSR/RTS or BOTH and they will never tell what they want. Driving me crazy an i gotta find my RS232 line detector box. Where did i leave that. Mayby Radio Shack still sells them. This box i have has erery possible configuration via soft control but there are thousands of possabilities. Gotta just try i guess. Currently FULL DUPLEX four line control don't work with anything, not even Hyperterm on HW control: once again they don't say what HW control means exactly .. just hook it up they say ... and it don't work. "hardware" or "software" but NONE tell what those define. arrrrgggg Best

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G'day, Yes, this data transfer thing can be a little tricky. It can depend on how the two devices are connected. What hardware lines do you have? ie what is the pinout of the calculator (we can work out the PC end). Does it have a full RS232 output or just 3 pins? Can you get it to just send out a string of data at a known baud rate? Don't worry about the binary vs ASCII thing right now; just set up a terminal program on the PC to receive data at a given baud rate and look at what is received. Jubalsams: if the calculator is RS232 compatible then you can get it to send data out at any given baud rate. If;however, the hardware dictates otherwise , then let us know. Good luck and don't forget to enjoy the Xmas Season.. elric

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Keep it simple and it will work. As you say, just use h/w handshaking protocol (from memory) 25 pin rs232:- 1 screen (not strictly necessary) 2/3 TX/RX 4/5 RTS/CTS 7 signal return 8 CD 20 DSR As you wish to transmit both ways, you may wish to double up connections. I would hardwire them on, except for RTS/CTS Oh the joys of the breakout box. Good luck - Keep us posted. Good luck - Keep us posted.

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