PJN5208

[lionelkjh]

Hello; I have a calibrator that I am restarting. The internal batteries to power it were dead. After replacing and loaded, it starts but it shows me "empty memory". The batteries are no longer charged for a very long time, which has resulted in the loss of the 9 measurement plans written in the internal memory of the calibrator. I think that to re-record these erased plans in RAM, it is necessary to use software with an RS232 port. My question is therefore: Would anyone have this software (because the calibrator should be almost 30 years old!), And most importantly, how to connect to the RS232 (because the connector does not correspond to our current computers? Thank you very much for your help because I am in a dead end (even 2 years after my first post on eevblog: I attached the photo)

[Whales]

Post a pic of the RS232 connector and a pic of the insides, we might be able to help better.

[lionelkjh]

The RS232 was removed when the batteries were unsoldered because the plug was completely corroded and broken. From memory, the solder plug was similar to a 3.5mm jack socket (photo) .....

[Whales]

It's not uncommon for UARTs to be done over 3.5mm audio jacks.  Three wires (GND, RX, TX) is often enough.  If the connector is no-longer there you can bypass it and tap wires onto the PCB yourself.

First you will want to grab a multimeter and measure the voltages of each wire compared to a known ground in the unit (whilst it's on).  This will tell you which wire is GND and what the signalling voltage levels are (proper RS232 or lower voltage).   RX and TX are typically both held 'high' to a voltage through internal resistors.

When it comes to working which way around RX and TX are: often you have to guess.  To avoid potential damage put some resistors (eg 1Kohm) in series.