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Cable Tester
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RS232 Pin Out | Connector Reference Guide
January 5, 2020 - Pin out diagram of a RS232 pin out with 9 pins d-sub connector (male & female). Also includes references guide to RS232 max cable length.
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US Converters
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RS232 Pinout : U.S. Converters LLC, Serial Data Communication
Below is the pinout of a typical standard male and female 9-pin RS232 connector, this connector type is also referred to as a DB9 connector.
Discussions

db9 - How do I do the 6 pin RJ11 to RS232 female serial adapter wiring? - Electrical Engineering Stack Exchange
These adapters work well, I have used them for RS232 many times before. As far as the pin out of the RJ11 you need to see what device it connects to and which pins correspond to the db9. The standard db9 pin out can be either a male or female connector and also DTE or DCE. More on electronics.stackexchange.com
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Confused about proper pinout with an RJ45 to DB9 adapter
I am attempting to control a device with RS232 commands. The device has a control box that accepts RJ45 cable. I am sending my commands via a Global Cache iTach WF2SL device which has a DB9 serial port. I am attempting to connect the two devices using a Cat-6 T-568B cable, and a RJ45 to DB9 adapter. More on community.spiceworks.com
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4
March 18, 2025
Omron sysmac cable
you need a link module to connect to it. you canโ€™t connect to that pin header directly More on reddit.com
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8
5
July 17, 2024
How do I un-null modem a null modem cable?
The cost of serial cables is quite trivial compared to the investment required to convert the null into a straight. If one wishes to go even cheaper, they have been seen in the patch cable/wall adapter/game controller section of Goodwill and others. More on reddit.com
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July 21, 2023
People also ask

What does the RS in RS 232 stand for?
RS (recommended standard) was developed by Electronic Industries Association back in the 60โ€™s to facilitate communication between a modem and computer terminals.
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eltima.com
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RS232 Pinout and Specifications Guide
Does RS232 play any role in modern computers?
Most industrial automation and surveying laboratories continue to use serial port technology in spite of its limitations. The re-introduction of DB-9M connector on the Tecra personal computer by Toshiba proves that these standards are here to stay for now. Despite their differences both USB and RS-232 standards support most software programs in major operating systems.
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eltima.com
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RS232 Pinout and Specifications Guide
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Decisive Tactics
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DB-9 Connector Pinout - Decisive Tactics, Inc.
Below is the pinout of a typical 9 pin RS-232 connector, this connector type is also referred to as a DB-9 connector. A computer's COM port (DTE) is usually male, and any peripheral devices you connect to this port usually have a female connector (DCE).
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Pinterest
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RS232 Female Connector Pinout
RS232 Female Connector Pinout | Com25 connector pinout diagram, Serial port wiring diagram, Serial cable connection diagram ยท Skip to content ยท When autocomplete results are available use up and down arrows to review and enter to select. Touch device users, explore by touch or with swipe ...
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Extron
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9-pin D Male to Female RS-232 Cable Guide
Extron Electronics, USA ยท 1230 South Lewis Street ยท Anaheim, CA 92805 ยท 714.491.1500 ยท Fax 714.491.1517 ยท Extron Electronics, Europe ยท Beeldschermweg 6C ยท 3821 AH Amersfoort ยท The Netherlands ยท +31.33.453.4040
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Eltima
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RS232 Pinout and Specifications Guide
3 weeks ago - An RS-232 device is either as a Circuit-terminating Equipment (DCE) or as a Data Terminal Equipment (DTE) depending on which wires are used to send and receive each signal. In accordance with RS-232 standard, DCE is meant for female connectors, and ...
Rating: 5 โ€‹ - โ€‹ 367 votes
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Aggsoft
aggsoft.com โ€บ rs232-pinout-cable โ€บ RS232.htm
RS232 Port (DB-25). Pinout and Signals
Explore the complete pinout, wiring, and signal details for the RS232 DB25 serial port. Get the essential information you need to check or build a cable.
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Aggsoft
aggsoft.com โ€บ rs232-pinout-cable โ€บ nullmodem-db9-to-db9.htm
RS232 Null Modem Cable Pinout (DB9-DB9)
Discover the pinout and signal configurations for creating a reliable RS232 null modem cable, connecting devices with 9-pin DB9 connectors.
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PBXDom
pbxdom.com โ€บ blog โ€บ engineering โ€บ rs-232-cables-wiring-and-pinouts
RS-232 Cables, Wiring and PinoutsRS-232 Cables, Wiring and Pinouts - PBXDom
May 24, 2021 - These diagrams show the male (grey background) and female (black background) pin numbering for DB9 and DB25 sub-miniature connectors. Generally Pin 1 is marked on the front of the connector right next to the pin โ€“ though you may need a magnifying ...
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  1. Note what Olin says - why do this? You may have a good reason but (as noted below) RJ11 is non standard for this purpose and you are inviting compatability problems.

  2. There is NO RJ11 serial data standard. See examples below.

  3. Advising whatyou want to connect to and why may make this task FAR easier.

  4. Example at end of RJ11 serial data pinouts.

  5. Brief comment below on finding unknown pinouts.


The answer to your question is given on the blackbox page that you referenced

  • Pin your own modular adapter to connect your serial equipment.

The reason that they did not connect the RJ11 connector to the DB9 is that there IS no standard way available.

The reason that they left the wires uncommitted was so that you could connect them in the way that suits you.

If you do not know what the pinout you need is, who does? (Really). What are you connecting the RJ11 circuit to? What equipment? / model? / brand? Do they provide a datas sheet or connection diagram?

Worst case you may have some equipment that has a serial circuit on an RJ11 connector that you want to connect to. In this case, the very best method is to get the manufacturer's information. If this is not available then there are ways to proceed.


Finding the pinout of a 6 pin serial connector.

This is just an overview -m knowing the equipment brand and model or, failing that, type of equipment and intended use will help geatly.

  • 6 wire connector.

  • Power off. Do any wires make low resistance connections with device chassis? Label as possible grounds.

  • Power on. Is any line at -5 to -12V wrt chassis ground. If only one this is probably TXD. Compare to diagrams below. Any clues?

  • If more than one low line one may be CTS or RTS or similar. With scope on check lines on turn. Depending on equipment TXD may have data burst. RTS may toggle or play around during startup.

  • etc.

More on this if needed.


Examples - these are useful mainly to show how thoroughly non standard the various arrangements are.

Dell RJ11 - one implementation


H2Ns page describing their RJ11 serial pinout and connections for interfacing to other equipment

H2NS's contribution to the fun.


Here's an interesting page from Unitronics they have a number of somewhat different "arrangements"

Here's a plug pinout from one of their several arrangements - it's notable for being different from but similar to the Dell arrangement above. TXD and RXD are the same and there's some other partial similarities.


  • CISCO RJ45 (NB not RJ11) (from)

    1 n.c. <- 7 RTS bn

    2 DTR <- 4 DTR bn/wh

    3 TxD <- 3 TxD gn

    4 GND 5 GND bl/wh

    5 GND 5 GND bl

    6 RxD -> 2 RxD gn/wh

    7 DSR -> 6 DSR or

    8 n.c. -> 8 CTS or/wh

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The db9 connector will have the pin position numbers stamped on the front of the connector. They can be seen with a magnifier. The pins are inserted from the rear of the connector into the appropriate pin hole. Care should be taken to insert the correct pins as they can not be removed without a removal tool. These adapters work well, I have used them for RS232 many times before. As far as the pin out of the RJ11 you need to see what device it connects to and which pins correspond to the db9. The standard db9 pin out can be either a male or female connector and also DTE or DCE. You need to know what you are connecting to before you can determine the correct wiring.

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Amazon
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Amazon.com: Custom Pinout DB9 Female to Mini Din 6-Pin Male RS232 Serial Cable, 26AWG Oxygen-Free Copper, Nickel/Gold Plated โ€“ CE/RoHS/UL Certified (6 ft/1.8M) : Electronics
โœ” High-Quality Materials โ€“ 26AWG oxygen-free copper conductors with PVC jacket for durability and minimal signal loss. โœ” Premium Connectors โ€“ Nickel-plated DB9 female + gold-plated Mini Din 6-pin male contacts for corrosion resistance.
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Zytrax
zytrax.com โ€บ tech โ€บ layer_1 โ€บ cables โ€บ tech_rs232.htm
Tech Stuff - RS232 Cables and Wiring
Brief tutorial and pinouts for RS-232, RS422/485, T1/E1 and V.35. If you want to know more about RS 232 signals then this page may help - but you may also need to lie down in a darkened room afterwards. DTE (PC) and DCE (Modem) DB9 and DB25 Male and Female Pin Numbering ยท RS232 on DB25 Pinout (RS-232C) RS232 on DB9 Pinout (TIA - 574) RS232 on RJ45 (RS-232D TIA-561) RS232 DB25 NULL Modem Pinout ยท
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Amazon
amazon.com โ€บ DTECH-Serial-Female-Straight-Through โ€บ dp โ€บ B07B4VXNLS
DTECH 6 ft RS232 Serial Cable Female to ...
DB9 rs232 cable female to female ... Through cord is pin-to-pin wired as a 9 pin serial cable Straight Thru (pinout :1-1, 2-2, 3-3, 4-4,......, 8-8, 9-9, G-G); standard shielded with AL foil...
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Virtual COM Port Driver
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All you have to learn about serial connector pinouts
October 3, 2024 - RS232 manages communication flowing between the DTE and DCE using serial pinouts of either the DB9 or DB25 variety. These D-sub connectors can terminate with an RS232 female pinout or DB25 or DB9 male connector pins. Each pin in a 9 or 25 serial ...
Rating: 5 โ€‹ - โ€‹ 367 votes