SWF Direct Cable Connection

For us to transfer .dst stitch files to our SWF machines we use a 9 pin null modem cable with female connectors on both ends.

The standard computer uses a male  9 pin connector for its serial port. It’s the same for SWF embroidery machines.

Null Modem Cable

A null modem cable is frequently called a crossover cable. It is used to allow two serial Data Terminal Equipment (DTE) to communicate with each other without using a modem  in between. For this to happen, the Transmit pin of one device is connected to the Receive pin of the other device. To enable hardware handshaking between the two devices, the Request to Send  pin of one device is connected to the Clear to Send pin of the other device. Because these pins are “crossed” on the two cable connectors, the term crossover cable was given.

Pin Functions for RS-232 Data
TX (pin 3 ) Serial Data Output
RX (pin 2 ) Serial Data Input
RTS (pin 7 ) Request to Send
CTS (pin 8 ) Clear to Send
DSR (pin 6 ) Data Set Ready
DCD (pin 1 ) Data Carrier Detect
DTR (pin 4 ) Data Terminal Ready
GND (pin 5) Ground

Null Modem Cable with Full Handshaking  2 variations

null modem cable

Pin 1 to Pin 1 null modem cable

Null Modem Cable

Female Connector front face view and back wiring pin 1 to pin 6

Female DB9

Front Face DB9 showing pin numbers

RX 2:———————–:3 TX
TX 3:———————–:2 RX
DTR 4:——————–:6 DSR
GND 5:——————–:5 GND
DSR 6:——————–:4 DTR
RTS 7:——————–:8 CTS
CTS 8:——————–:7 RTS

RS232 serial communication protocol

RS232 is the most common serial interface and is standard on most Windows compatible desktop computers. It only allows for one transmitter and one receiver on each line and uses a Full-Duplex transmission method. RS232 is used for many purposes, such as connecting a mouse, printers, scanners or modems, as well as industrial instrumentation. With improvements in line drivers and cables, applications often increase the performance of RS-232 beyond the distance and speed listed in the standard.

Com Port Settings for SWF machines

Baudrate: 38400
Data Bits: 8
Stop Bits: 1
Parity: NONE
Handshaking: HARDWARE

Just for some clarity DTE, DCE 

DTE – Data Terminal Equipment; DCE – Data Communications Equipment.

DTE and DCE are the two sides of an RS-232 interface. It is important to differentiate between the two because the pin outs for the cables are physically different, as are the  handshaking process and interfacing. A modem is an good example of a DCE device. And a common DTE device is the serial port on a computer.

Wiring a DTE device to a DCE device for communication is easy. The pins are a one-to-one connection. A straight through cable is commonly used for this application. In contrast, wiring DTE to DTE  requires crossing the transmit and receive wires. This cable is known as a null modem or crossover cable.



9 thoughts on “SWF Direct Cable Connection


  2. If making your own cable the drawing does not show pin 1 connection. Pin 1 should connect to pin 6 on the connector.

    Or you could just purchase a cable here


    SCNM9FF Data Transfer Cable – Serial Null Modem Cable DB 9 Female DB 9 Female 10ft

    Drawing updated to show pin 1 and 6 connection.

  3. Tried the trial version, download okay, installed, browse design, send to machine,
    status says com1 working and okay, device com1 not working. done steps by instructions for machine to receive data, after hit setup etc. goes back to menu.
    checked my cable pin outs to be sure it was correct and it is.
    We could use some help here for we would really like the software to work for us.

    • Hi and thanks for trying out this utility.
      If status says com 1 “not working” then com1 is not working. The first Ok is checking to see if their is a com port. The second test is to see if it can be configured. so this means the com port may be in use by something else. so it is not available. If you try turning the pc off and back on then try the software again.

      • There are an unlimited number of things that can be using the com port. modem software,cell phone software, syncing software for mobile devices, printing software, plug and play hardware, on and on.

        1. try and find the software or hardware that’s using it and disable it so other devices can use it.
        2. Uninstall the com port in device manager, and re install it. This should allow the sTx to utilize it.

        In this case the problem was a virtual PDF printer that was installed by another app. It was found when looking at the printer properties.

    • Yes, we now have the Multi port update for sTx available. This allows you to configure three ports of your choosing.

  4. I have downloaded the trial that I am using to make sure I can make this work before I purchase the full version. It would appear that the file is transferring to my SWF machine but it is a jumbled mess of stitches showing up on the screen instead of the design. Any ideas?

Leave a Reply

Your email address will not be published. Required fields are marked *


five × 9 =

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>