As a professional digital speedometer supplier, we would to introduce differences in details.
An electrical speedometer reads pulses (signal) from the signal source. This is read by a processor which drives the pointer (not a needle) and odometer to do the right things. The electronic speedometer is either permanantly programmed to read a specific number of pulses per mile (or kilometer) and read a certain speed; or it may have an external switch, or DIP-switches, that can be altered to change the vehicle speed reading on the dial. While this works well if you know the exact number of pluses coming from the sender, some trial and error may be required. The difficulty in this is with so many types of senders being spun by different sized tires, rear end gears, final drive, etc, it is nearly impossible sometimes to know where to start. Electronic speedmeters read pulses per mile (PPM) and the range can vary from 3000-200,000 per mile, quite a gap to fill.
A programmable electronic speedometer operates in a similar way but has the added feature of user-directed programming. All NVU electronic speedometers are fully programmable. The speedometer can be programmed to the proper sender input by driving a mile or by entering the pulse count manually. The drive-a mile technique is the preferred method as this will give the most accurate result provided the mile is indeed a mile. This method will also be completed in the time it takes to drive a mile, about a minute or two! Other features can be programmed into NVU electronic programmable speedometers; service intervals, speed warnings, integrated tripmeters can all be set by the push of a button. If any electronic speedometer adjustment is required, the drive a mile function can be re-calibrated again or at any time there is a change to the vehicle like gears or tire size. Its just that easy. All NVU electronic speedometers used in aftermarket kits have these features.