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

Answer from Russell McMahon on Stack Exchange
Top answer
1 of 2
4
  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

2 of 2
1

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.

🌐
Tekram USA
tekram.com › home › cables › tekram usa rj11 to rs232 cable
Tekram USA RJ11 To RS232 cable
Tekram USA RJ11 To RS232 cable
RJ11 To RS232 / DB9 9-Pin Serial (Female) Cable Assembly adapter Features: RS-232 / DB9 9-Pin Serial (Female) to RJ-11 Cable Connectors: DB9 9-pin female to RJ-11 Cable Length: 5 feet/ 1.5 meter length Assembly: Adapter E91242 AWM 20251 60C 150V 26AWG Data Rate: Supports standard RS-232 data rates Construction: High-quality materials for durability and reliable performance Compatibility: Compatible with devices using RS-232 serial communication and RJ-11 connectors Shielding: Adequate shielding to minimize electromagnetic interference (EMI) Pin Configuration: Standard RS-232 pinout for DB9 fe
Price   $14.99
Discussions

Finding RS-232 pinout on an RJ11 connector
This submission has been allowed provisionally under an expanded focus of this sub (see column "G" in this table ). OP, also check if one of these other subs is more appropriate for your question. Downvote this comment to remove this entire submission. More on reddit.com
🌐 r/AskElectronics
10
2
February 12, 2024
Поиск распиновки RS-232 на разъеме RJ11
Сабреддит для практических вопросов по электронным схемам на уровне компонентов: проектирование, ремонт, покупка компонентов, измерительное оборудование и ... More on reddit.com
🌐 r/AskElectronics
10
2
February 12, 2024
Communicating with an rj11 device over rj45 (ethernet) port
I have a Brink heat recovery installation that has an rj11 port which is used to set the installation to it's various settings (setting 1, 2 and 3)… More on reddit.com
🌐 r/linuxquestions
2
1
December 27, 2018
Connect to APC PDU RJ11 port. Do some cables with USB exist? or can i use Serial/USB adapter?
Can i just use a simple serial to USB connector? Yes but you will need the APC serial cable for the PDU. Unfortunately I never found a third party that worked reliably so I kept hundreds of these things in the datacenter. More on reddit.com
🌐 r/sysadmin
17
1
July 26, 2018
🌐
Alzatex, Inc.
alzatex.com › ps1db9b
RS232 to RJ11 CONVERTER Module (ps1db9b)
RS232 to RJ11 CONVERTER Module (ps1db9b)
RS232 to RJ11 converter module with one DB-9, 2 RJ11(6-pin) jacks and power supply connection in a plastic enclosure. Features Transmit serial data for 200ft or more over RJ11 telephone cable. Converts RS232 serial data to RJ11. Converts RJ11 to RS232 serial data. Baud rates up to 19,200(Baud rate may be limited by distance). Power from either end. Transmits power and data over CAT-5. Works with all Alzatex products that have the RJ11 serial data accessory connector. Specifications DB9 jack for RS232. RJ11 jack for data TX on D1, RX on D3. RJ11 jack for data RX on D3, TX on D1. Power trans
Price   $165.00
🌐
eBay
ebay.com › itm › 267371207362
RS232 Serial to RJ11 Adapter | eBay
RS232 Serial to RJ11 Adapter
The RS232 Serial to RJ11 Adapter is a 1:1 connection adapter designed to convert RS232 serial connections to RJ11, allowing for easy connectivity to devices requiring serial communication.
Price   $6.98
🌐
My Cable Mart
mycablemart.com › store › cart.php
My Cable Mart - DB9-Male to RJ11/12 (6 wire) RS232 Modular Adapter Ivory
This modular adapter has a DB9 male connector that plugs into DB9 RS232 serial port and converts it to an RJ11 or RJ12 connection.. . RJ12 Pinout. . Pin1 -- White. Pin2 -- Black. Pin3 -- Red. Pin4 -- Green. Pin5 -- Y
🌐
Amazon
amazon.com › Poyiccot-Adapter-Sevo-Drive-Lead-Shine-Communication › dp › B0CCS6SXHM
Amazon.com: Poyiccot DB9 to RJ11 Serial Adapter Cable, RS232 DB9 Female to RJ11 RJ12 6P6C LAN Network Serial Control Cable for Sevo-Drive Lead-Shine Stepper Communication, 6Feet : Electronics
No need to install driver,plug and play. DB9 to RJ11 6P6C Adapter Cable is mainly used to connect the Telephone Modular Plug RJ11 RJ12 6P4C Connector to DB9 9 Pin RS-232 Serial Control jack port.
Find elsewhere
🌐
My Cable Mart
mycablemart.com › store › cart.php
My Cable Mart - DB9-Female to RJ11/12 (6 wire) RS232 Modular Adapter Ivory
This modular adapter has a DB9 male connector that plugs into DB9 RS232 serial port and converts it to an RJ11 or RJ12 connection.. . RJ12 Pinout. . Pin1 -- White. Pin2 -- Black. Pin3 -- Red. Pin4 -- Green. Pin5 -- Y
🌐
Campbell Scientific
campbellsci.com › 34540
34540 - RJ-11 to RS-232 DB9 Female Converter
The 34540, manufactured by Morningstar, converts a controller's meter port (RJ-11 phone-type connector) to a standard RS-232 serial connector for connection to...
🌐
Amazon
amazon.com › CineRAID-RS-232-RJ-11-Cable-Meters › dp › B07812PVN6
Amazon.com: CineRAID RS-232 to RJ-11 Cable (1.5 Meters/5 feet) : Electronics
Mendouconert DB9 Serial Cable for Hirschmann Managed Switch, RS232 Serial to RJ11, V.24 Management Configuration · DB9 Serial RS232 to RJ12 6P6C Adapter Cable for APC PDU 940-0144A
🌐
Amazon
amazon.com › Suamdoen-DB9-Adapter-Mega-fabs-D1-DNT07A › dp › B088BBWRFP
Amazon.com: Suamdoen DB9 RS232 to RJ11 Adapter Cable for Mega-fabs D1 Servo Driver D1-DNT07A D1 DNT08A : Electronics
db9f rs232 to rj11 adapter cable for mega-fabs d1 servo driver Length:6ft/180cm this link is for D1 DNT07A D1-DNT08A Package: 1 x DB9 to RJ11 6P6C cable for Mega-fabs D1 DNT08A Cable
🌐
ABRA Electronics
abra-electronics.com › wire-cable-accessories › wirecable › rs232-extension-cables-en › rj11-usb-cable.html
CAB-RJ11-USB USB to RS232 to RJ11 Conversion Cable for Stepper/Servo Drive
USB RS232 to RJ11 Conversion Cable for Stepper/Servo Drive
USB RS232 to RJ11 Conversion Cable for Stepper/Servo Drive, 180cm This is an USB to RS232 to RJ11 cable adaptor. It uses an FTDI FT232 chip to convert USB signals to RS-232 Serial which is accessible at the RJ11 male connector. This type of cable is commonly used for stepper motor drivers such as DM432C, DM442, DM556, DM856, 3DM683,  AM882,  DM1182, and DM2282 as well as servo motor drivers including DCS810, DCS810S, ACS306, ACS606, and ACS806.
Price   $27.07
🌐
CardMachineOutlet.com
cardmachineoutlet.com › products › cbl-810278-001
Cable MDIN-9F to RJ11 Plug RS232 Adapt (CBL-810278-001) | CardMachineOutlet.com
Cable MDIN-9F to RJ11 Plug RS232 Adapt (CBL-810278-001)
Cable MDIN-9F to RJ11 Plug RS232 Adapt (CBL-810278-001)
Price   $15.39
🌐
Amazon
amazon.com › serial-rj11 › s
Amazon.com: Serial To Rj11
USB DB9 RS232 to RJ11 RJ12 Serial Cable for Leadshine Servo Stepper Motor DM432C DM442 DM556 6FT (USB to RJ12 - with FT231XS Chip) · USB to RJ11 RJ12 6P4C Adapter RS232 Serial Console Cable 940-0144A for PDU AP77XX AP78XX AP79XX AP86XX AP88XX AP89XX(1.8m) · USB RS232 to RJ11 Serial Converter ...
🌐
Vinatoru
vinatoru.com › home › accessories, accessories › data cable › rs232 (9 pin (f)) to rj11 connector
RS232 (9 pin (F)) to RJ11 Connector | Vinatoru Enterprises, Inc.
RS232 (9 pin (F)) to RJ11 Connector
This cable connects to Applied Motion step motor drives (ST5-Q-NN, STM23Q-2AN) for purposes of communication and programming.
Price   $75.00
🌐
eBay
ebay.com › electronics › computers/tablets & networking › computer cables & connectors › parallel, serial & ps/2
DB9 RS232 Serial 9 Pin Male to RJ11 Female Adapter Converter | eBay
DB9 RS232 Serial 9 Pin Male to RJ11 Female Adapter Converter
The DB9 RS232 Serial 9 Pin Male to RJ11 Female Adapter Converter is a blue adapter that allows you to connect a serial (RS-232) male connector to an RJ11 female connector. This 1:1 adapter converter is designed to simplify the process of connecting ...
Price   $3.99
🌐
Walmart
walmart.com › ip › DB9-Female-to-RJ11-12-6-wire-RS232-Modular-Adapter-Ivory › 720306539
DB9-Female to RJ11/12 (6 wire) RS232 Modular Adapter Ivory - Walmart.com
DB9-Female to RJ11/12 (6 wire) RS232 Modular Adapter Ivory
This modular adapter has a DB9 male connector that plugs into DB9 RS232 serial port and converts it to an RJ11 or RJ12 connection. · RJ12 Pinout: · Pin1 -- White · Pin2 -- Black · Pin3 -- Red · Pin4 -- Green · Pin5 -- Yellow · Pin6 -- Blue · * Gold plated pin · * 28AWG wire · * Molded ivory color housing · * Thumb screw
Price   $7.52
🌐
Veexinc
kb.veexinc.com › en › knowledge › what-is-the-rj11-rs232-port-used-for
What is the Application for the TX300s' RJ11 RS232 Serial Port?
If an RS232 port with 1PPS output is the only option available from an older switch, GPSDO or PRTC clock source, a simple passive adapter cable could be built by using a UTP pair to connect the device's 1PPS output signal to pin 2 of the TX300s' RJ11 plug and ground to pin 4, using one twisted pair.
🌐
Reddit
reddit.com › r/askelectronics › finding rs-232 pinout on an rj11 connector
r/AskElectronics on Reddit: Finding RS-232 pinout on an RJ11 connector
February 12, 2024 -

I have an ancient 90's era SMARTBoard that uses an RS-232 over an RJ11 connector. There is almost no documentation online about this model, let alone pinout for the data connector. (Model is SB-2/SB-3 or 300 series)

What do I need to start figuring out the pinout for this?

I've got plenty of tools, USB to serial adapters, etc. I've already made a RJ11 pigtail that I can connect to an oscilloscope, but I have no idea what i'm doing.

This image doesn't really help, but here it is anyway: https://i.imgur.com/WNuGRax.jpeg

Full album: https://imgur.com/a/j5eAqOV

Edit: I pulled the board and uploaded images to the album. There's a chip labeled MC145407 "5 Volt Only Driver/Receiver"

I've mapped the pins on the RJ11 to these pins on the IC

  • 1 Rx1

  • 2 Rx3

  • 3 Rx2

  • 4 Tx2 (-9.95v)

  • 5 GND

  • 6 Tx3 (+9.95v)

🌐
Newegg
newegg.com › home › components & storage › cable › serial cables › jxeit
USB RS232 to RJ11 RJ12 6P6C Programming Cable for Keyence PLC to PC Communication, FTDI Chip Built-in - Newegg.com
USB RS232 to RJ11 RJ12 6P6C Programming Cable for Keyence PLC to PC Communication, FTDI Chip Built-in
USB RS232 to RJ11 RJ12 6P6C Programming Cable for Keyence PLC to PC Communication, FTDI Chip Built-in
Price   $30.60