Calculator blog

Continuing with the programming cable: I received pictures of some parts as they were being produced by the manufacturer. These are the circuits used for the two buttons in the cable: the Reset and Erase buttons.

The clip was also extensively desgined and tested in several materials and shapes before finally commiting to a mould. The producer estimated that the 0,4mm diameter pin was too thin for repeated use, se we brought it up to 0,6mm. I concur: in the past some pins in 0,4mm were easily bent and I destroyed a couple of cables.

The head of the cable is asymetrical so there is one way only to insert it.

As you know, we have designed a cable for the newest Voyagers' reprogramming. The calculator side has a POGO 6-pin connector, and the computer side has an USB A connector. (maybe too early for an USB C connector?). We have had several redesigns to improve connectivity, useability and resistance - all which has delayed the delivery until now. We expect to receive the initial units around January the 15th, and these will be sent to the customers that placed an order before. 

With the cable you can reprogram the HP12c and HP15c CE of latest versions. You can alter the firmware, or, most likely, fix bugs. The only "important" bug we know about in the hp15c is not in the supported HP15c 99 register mode - it is in the HP16c unsupported mode. This bug is quite nasty - it renders the DEC mode completely unusable. Fortunately a member of the hpmuseum.org forum found a simple fix, which implies just 3 byte changes. I have been using a prototype of the cable to fix more than 120 units for my customers and I have to report that I have not "bricked" any calculator in the process. For comparison, I have bricked beyond recovery many calculators HP15c Limited Edition or HP30b financial calculator. The new modules are much more robust.

Pricing will be depending on whether the customer buys a HP15c from us: 40€ if he doesn't, 20€ if he did and 10€ in a special package with the calculator.