Pinouts

Over the years, I have collected many pinouts for all sorts of interfaces, connectors, jacks, etc.  These are all stored on my laptop and on my smartphone.  It is easy enough to look these things up online, however, there are occasions when the internet is not available for whatever reason.  Thus, this is my collection of pinouts, many of which have been adapted from Wikipedia articles.  Many times I put things here for my own use.  However, if I have spent ten minutes looking for the USB pin out on my smartphone, someone else has done the same thing.  Most of these images have higher resolutions available.

Enjoy!

EIA/TIA 568a and b ethernet cable standard
EIA/TIA 568a and b ethernet cable standard

Standard networking connectors for Ethernet connections. Rumor has it that only the “A” standard is accepted for government work and the “B” standard is being depreciated.

803.3af Power over Ethernet, imposed on EIA/TIA 568 a and b
803.3af Power over Ethernet, imposed on EIA/TIA 568 a and b

Power over Ethernet pinouts. More and more commonly used in VOIP phone systems, but can also be found in wireless access points and other things of that nature.

10/100 base T cross over cable
10/100 base T cross-over cable

Ethernet crossover cables are useful for connecting to similar pieces of equipment together, e.g. a computer to a computer, or a switch to a switch. Many new switches have port sensing, which will automatically cross the connection if a straight through cable is used.  Others have a specific port or a switch for a specific port which will cross over the cable.  Gigabit Ethernet uses all four pairs, thus a 1000 base T crossover looks a little bit different.

10/100/1000 base T Ethernet crossover cable
10/100/1000 base T Ethernet crossover cable

This type cable is backwards compatible with 10/100 base T systems.

Registered Jack 11/14/25
Registered Jack 11/14/25

Telephone system equipment jacks.

Registered Jack (RJ) 48, commonly used on T-1 and ISDN circuits
Registered Jack (RJ) 48, commonly used on T-1 and ISDN circuits

RJ48 and 48X used on T-1 (DS-1) and ISDN connections.  Since BRI and PRI ISDN are two wire circuits, the active pins are 4/5, which is the same as an RJ11.  I have often used RJ11 jacks for ISDN and found no issues with doing so.

T-1 (DS-1, DSX-1) crossover cable
T-1 (DS-1, DSX-1) crossover cable

Crossover cable for T-1 (DS-1 or DSX-1 interface). Note, this is different from an Ethernet crossover cable, which will not work for in a DS-1 interface.  A T-1 loopback connector goes from pin 1 to pin 4 and pin 2 to pin 5 on a 8P8C connector.

RJ21 and 21X color code.
RJ21 and 21X color code.

RJ21 and 21X connectors are often found on the side of punch blocks and make for quick connections on cabling trunks.

25 pair color code
25 pair color code

The generic 25 pair color code, which is always a good thing to have.

RS-232 data pins out for various connectors
RS-232 data pins out for various connectors

RS-232 is still commonly used for data transfer in broadcast facilities. RS-485 is also used, however, that standard is often used with screw terminals or some other generic connection.

Null modems, cables and pinouts
Null modems, cables and pinouts

Null modems for connecting equipment together and testing.

Universal Serial Buss (USB) connections and pinouts
Universal Serial Buss (USB) connections and pinouts

Various USB connectors and pinouts. USB has replaced RS-232 data ports on most newer computers.

VGA connector and pinout
VGA connector and pinout

Computer graphics card pinouts.

Computer Parallel port pinout
Computer Parallel port pinout

Computer parallel port pinout, not used very much anymore, replace by mostly USB devices. Can also be used as a limited GPI/GPO interface.  Some small automation software programs use pins 10,11,12,13 and 15 for closure information and pins 1, 14, 16, and 17 for output switching, machine starts and the like.

PS2 mouse and keyboard connector
PS2 mouse and keyboard connector

PS2 mouse and keyboard connectors, again, replaced by USB but still found on older motherboards.

RJ-45 to balanced analog and digital audio
RJ-45 to balanced analog and digital audio

RJ-45 to balanced audio. This is a fairly standardized audio application for RJ-45 connectors developed by Radio Systems/Studio Hub. It is also used by Telos/Axia and Wheatstone, although often the +/- 15 VDC power is not included.

XLR connectors, old technology, still used
XLR connectors, old technology, still used

The ubiquitous XLR connector, still used for analog audio and also AES/EBU digital audio.

Quad Star Microphone Cable

Or Star Quad Microphone Cable, depending on who is making it.

Star Quad Microphone Cable diagram
Star Quad Microphone Cable Diagram

This has been around for quite a while, but many studio/broadcast engineers don’t understand it or don’t use it for some reason. Microphones and mic pickups produce relatively low signals when compared to line-level audio.  Most microphone preamps have a gain of +50 dB, which means any noise gets amplified and even small things can become major problems quickly.

Gepco MP1201 Quadstar Microphone Cable
Gepco MP1201 Quadstar Microphone Cable

Under general conditions, most balanced shield twisted pair (STP) audio cable such as the standard Belden 8450 is adequate for stationary microphone cable for short runs.  When the cable is not permanently fixed in place, as in hand-held microphones, microphones mounted on booms, or other nonfixed microphone applications, then a flexible cable must be used.  Star Quad cable has better noise specifications than standard flexible microphone cable.

The advantage of Star Quad cable for low-impedance microphones (150 ohms) is that the parallel twisted pairs significantly reduce inductive reactance.  In AC circuits, inductive reactance acts as a low pass filter, gradually rolling off as the frequency is increased.  This effect is cumulative, the longer the cable run, the more inductive reactance is added to the circuit.  The result is microphone audio can have smeared or ill defined high frequency audio.

parallel inductance formula
parallel inductance formula

Using two parallel twisted pairs is similar to parallel resistors when it dealing with inductive reactance, it halves the value.

In addition to reducing inductive reactance, the tighter twist found in Star Quad cables reduces the CMRR by about 20 dB.  The Star-Quad configuration keeps the conductors in the same relative position to each other as the cable is flexed and moved around.  All of this makes it superior to standard STP microphone cable.

Several companies manufacture Quad Star cables:

  • Belden: 1192A
  • Canare: L-4E6S
  • Gepco: MP1201
  • Mogami W2534
  • Cardas 4X24

The price of Star Quad cables runs about 40-60 cents per foot (more for the Belden, much more for Cardas) if purchased in bulk.  That is about the same range for two conductor mic cables.

As good as this cable is, I don’t think they had this in mind when they made it:

I wonder what the centripetal force on that cable is when the microphone is in full motion. Also, I’d bet that SM58 was none the worse for were after it’s crowd surfing moment.