HP 48 Port Pinout

[thomasross]

Hi,

According to this PDF, there is no conversion between the serial end and the HP 48 end of the cables, they just connect directly to each other.

I have a serial to USB adapter, so if I connect some wires from the HP 48 to the serial to USB adapter (properly according to the pinout) it should work.

Can anyone verify this? Has anyone tried it?

[EugeneNine]

Yes, USB to serial works fine, I have an QVS (microCenter) brand USB to serial and an adapter and it works fine

[thomasross]

(03-28-2017 11:33 AM)EugeneNine Wrote:  Yes, USB to serial works fine, I have an QVS (microCenter) brand USB to serial and an adapter and it works fine

Sorry, not quite what i meant. I meant can you put wires directly from the port on the calculator into your serial to USB adapter and it will work?

[Han]

(03-28-2017 09:18 PM)thomasross Wrote:  Sorry, not quite what i meant. I meant can you put wires directly from the port on the calculator into your serial to USB adapter and it will work?

I don't think so. You should check this guide to see the electrical specifications of the HP48 ports.

http://www.hpcalc.org/details/4741

EDIT: I'm an idiot; we are referring to the same links... Ignore this post.

[EugeneNine]

Most USB to serial that come out into a DB9 like that are the +/- 12V style. The 48 was designed for those.

The ones like these https://www.arduino.cc/en/Main/USBSerial
are usually 5v or 3.3v.

You can see mine is just plugged in there, the tan adapter is just an adapter from RJ45 to db9 as well, there is no circuitry in it.

Its standard rs232

http://www.hpcalc.org/hp48/docs/faq/48faq-12.html

Or page 6 of the guide Han posted, the input is up to 15v tolerant, rs232 is 12v.