In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Zoot wrote:

There should be a font pre-installed for chars $00-$7F. Very surprised if that were not the case. My boards were empty (and waiting for my own fonts) in the upper half of eeprom. That's a side-issue, really.

I would look for simpler explanations first. Receiving the prompt may or may not be indicative, as my reading of the pre-installed SXB driver for the on-board SX has it returning a prompt after the receipt of any invalid serial command, as well as after executing a valid command.

In other words, the prompt can only mean one of three things: "powered up/reset: now ready" OR "valid command executed: now ready" OR "invalid command ignored: ready". The fact that you received 3 prompts in a row would lead me to think you are NOT correctly sending the serial commands, because this is what I would expect to see:

- inkjet board connected to usb, THEN powered up
- "ready" prompt received from board at terminal ">"
- transmit hex $02, 1-64 ascii bytes, hex $03 ("STX", string, "ETX")
- receive one "ready" prompt after *string is done printing*

Receiving 3 prompts, one for each part of your send, makes me think one or more of your sent bytes are not valid commands, and so the driver disregards each of them in turn and immediately returns a prompt (which is what it's supposed to do). I would look to correctly sending serial values first. I would look that STX/ETC are being sent correctly, because if STX is good, anything that follows is string (and therefore you can't have bad bytes). If the STX is bad, AND is not a valid command, then the following two bytes would also be "bad" and would return prompts. 

Does that make sense?

If you have a Stamp or an SX or something easy to program in BASIC, you could try hooking up the Stamp to the 3pin TTL serial header and see if it works using Parallax's demo BS2 program (which should work "right out of the box"). If that works, then your problem is definitely in your USB/byte transmission.

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