HP 48G - what next?

[pier4r]

2: the USB should be standard, the best thing is that you can power the calculator with USB only even without batteries. Only few casios (9860 and the cg50 once started), prime and nspire allow this.

3: As far as I remember yes. As long as the sd is under 4 GB it should work. Otherwise you should be able to find people that sell bunch of old but functioning sd cards. I still have a 256 mb sd in the 1st hp 50g that I giften to myself in Dec 2010. For the others I used a SD adapter for micro sd of 2gb picked from nokias that I am not currently using.