What is a jumper?

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?

jumper

kojow7

Posted 2018-10-01T04:34:34.697

Reputation: 220

2read it again. they both say the same thing. – Keltari – 2018-10-01T04:56:14.083

6@Keltari: I've read it several times and no they don't? – user1686 – 2018-10-01T04:56:40.973

@grawity actually they do. Both call the pins jumpers. the second calls the sleeve a shunt jumper. – Keltari – 2018-10-01T04:57:51.223

5@Keltari: The latter calls the pins "jumper pins", not "jumpers", which is quite different already. – user1686 – 2018-10-01T05:04:41.077

Your assumption that a "cover" is a "plastic cover" is incorrect. A shunt jumper (aka shorting block or header shunt) has metal inside it to short the two pins together. IMO the first quote is a dumbed-down explanation that is PC-centric and is otherwise vague. The pins are more often called header pins, at least that's the name I'd use to look them up in a parts catalog.

– sawdust – 2018-10-01T05:14:18.213

This question would better fit to [electronics.se] IMHO. – Melebius – 2018-10-01T10:30:03.303

Possible duplicate of What do you call the place on a hard drive (or motherboard, or anywhere else) to place jumpers?

– Melebius – 2018-10-01T10:31:34.957

Answers

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.

user1686

Posted 2018-10-01T04:34:34.697

Reputation: 283 655

Dictionary definitions also support the idea that it is the device that is creating the connection that is the jumper. Merriam-Webster (a connection used to close a break or cut out part of a circuit) and Collins (a short length of wire used to make a connection, usually temporarily, between terminals or to bypass a component) and Oxford (A short wire used to shorten an electric circuit or close it temporarily)

– Adam J Limbert – 2018-10-01T06:48:14.103

1Good answer. Since it is a heavy-on-opinions-question I'll hazard one as well: In all applications besides pcb's I have seen the name jumper - it is usually used to bypass something ("jump"). At work we often "jump" to seek for faults in a logic circuit. Typical case some pump should recieve an "OK" signal in the form of a standing 1 - and won't start until it gets one. So we provide it by "jumping" the signal. And some times we even use jumpers to correct faults, but that practice gets problematic if prolific. – Stian Yttervik – 2018-10-01T10:30:42.397

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

Posted 2018-10-01T04:34:34.697

Reputation: 161

"The plastic jumper electrically joins the pins" Might be a good idea to note the jumper isn't entirely made out of plastic. After all, it wouldn't connect the pins electrically if they were. The inside is usually a piece of copper, gilded copper or another metal. Looks like this.

– Mast – 2018-10-01T14:17:24.557