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Some documentation I read refers to the pin cover as a “jumper.” Other documentation I read refers to the pins themselves a a “jumper.”

For example, in the A+ Guide to Hardware by Jean Andrews it says:

A jumper is two small posts or metal pins that stick up on the motherboard, used to hold configuration information. An open jumper has no cover, and a closed jumper has a cover on the two pins.

However, on Wikipedia it says:

Jumper pins (points to be connected by the jumper) are arranged in groups called jumper blocks, each group having at least one pair of contact points. An appropriately sized conductive sleeve called a jumper, or more technically, a shunt jumper, is slipped over the pins to complete the circuit...When a jumper is placed over two or more jumper pins, an electrical connection is made between them.

So, in the first case it is the pins that are the jumper, but in the second case it is the cover that is the jumper. There seem to be many more cases which refer to the cover as the jumper, but there are a handful (such as the textbook above) which refer to the pins themselves as jumpers.

Which one of these is correct or are they both correct?

kojow7
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2 Answers2

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I'd say this is practically an 'opinion' thread, but...

The term "jumper wire" or "jumper cable" has long existed in other contexts such as vehicle jumper cables. The purpose of a jumper device is to connect two electrical contacts (jump the gap between them) – sometimes even if those contacts themselves have a different primary purpose.

Because the pins are fixed-position, they may be called "jumper pins" (if they're dedicated to this task), but they are not "jumpers" themselves – the cable/cover/sleeve/shunt is the one that jumps over the gap (and gets the name 'jumper' from that).

(As far as my English goes, it seems to be valid to interpret 'jumper pin' as "pin for use by jumper devices", but 'jumper wire/cable' as "wire/cable that is a jumper device")

Then again, terminology is made by people who use it, even if it doesn't end up being logical.

grawity
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Some jumpers to select Rs-485 biasing resistors

I think of jumpers as connectors to select characteristics on a PCB. Pic attached. Sometimes called shunt jumpers. The plastic covered jumper electrically joins the pins it is pushed onto (i.e. it has electrical contacts and a connection across it). In this picture there are two 'jumpers' and they set the `IN' option on RS485 biasing resistors.

Robin
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