Re: HP49G+ and HP49 are Compatible ?

christian_ab wrote:
> >>>> Is the IrDA interface capable to transfer with oldest HP48 series ?
>
> >No. Different protocols. It DOES work with the old calculator printers though.
>
> Seems to be impossible to connect directly an HP48G with a HP49G+
> directly, if the IrDA isn't compatible with the 48 series protocol,
> some electronics it's necessary to convert the USB port on the 48G+ to
> RS232 on 48 series....

You'll find that troublesome too. The USB port on the 48G+ is
configured as a device, not a host; your typical off-the-shelf
USB->RS232 converter will not work as expected.

It may be possible to program a smart USB-enabled microcontroller to
act as a limited USB host, with the sole purpose of enumerating and
talking to HP49g+'s, and forwarding all incoming and outgoing data
streams to an RS232 port that talks to the older HP48's.

It also may be possible to hack the OS of the HP49g+ so that the USB
connector acts as a host instead of a device. (The CPU appears to be
physically capable of using the USB pins in either host or device mode,
and it appears to only be the software that runs it which determines
which mode it operates in.) Then, you'd have to write drivers to allow
the HP49g+ to talk to an off-the-shelf USB->RS232 converter, and
connect the other end to the HP48 (along with some external power
supply, because it seems doubtful that the HP49g+ would be able to
supply sufficient power to drive such an adaptor on its own).

Finally, it may be possible to design a device that accepts IrDA
signals, and converts them to RS232 which is fed into the serial port
of the HP48.

- Luke

.

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