Set Custom Pinout

At “Custom pinout” tab you can set custom signal lines pinout, manage signal lines pinout by using pinout presets  and create your own pinout presets just in several clicks.

Custom pinout presets:

  1. Standard – Default signal lines pinout.
  2. Loopback Mode – Enables software think that there is handshaking available, though null-modem does not apply it.
  3. Custom – You can select your own pinout of signal lines and save it.

In Standard pinout preset, RS232 null modem scheme with partial handshaking is used:


Connector 1Connector 2Function
17 + 8RTS2arrow_rightCTS2 + CD1
55Signal ground
7 + 81RTS1arrow_rightCTS1 + CD2

In Loopback mode pinout preset, RS232 null modem scheme with loop back handshaking is used:


Connector 1Connector 2Function
55Signal ground
1 + 4 + 6DTRarrow_rightCD + DSR
1 + 4 + 6DTRarrow_rightCD + DSR
7 + 8RTSarrow_rightCTS
7 + 8RTSarrow_rightCTS

To set custom pinout, please, do the following:

  1. Switch to “Custom pinout” tab.
  2. Select the required virtual serial pair in the Serial Ports Explorer.
  3. Select one of the required signal lines from “IN side of the pair” list for internal serial port and tick the corresponding checkboxes at OUT side.
  4. To save settings, enter the desired preset name and click “Save preset” button.
Note: You cannot save your presets with “Standard”, “Loopback mode” or “Custom” names.
Note: Other null-modem schemes are available here.

Here is the list of signal lines and their interpretation:

  • RTS (Request to Send) – This signal is asserted (logic ‘0’, positive voltage) to prepare the DCE device for accepting transmitted data from the DTE device. Such preparation might include enabling the receive circuits, or setting up the channel direction in half-duplex applications. When the DCE is ready, it acknowledges by asserting Clear to Send.
  • DTR (DTE Ready) – This signal is asserted (logic ‘0’, positive voltage) by the DTE device when it wishes to open a communications channel. If the DCE device is a modem, the assertion of DTE Ready prepares the modem to be connected to the telephone circuit, and, once connected, maintains the connection. When DTE Ready is deasserted (logic ‘1’, negative voltage), the modem is switched to “on-hook” to terminate the connection.
  • OUT1 – signal is used only by specialized hardware (like the Hayes SmartModem internal board). The meaning of this bit is determined by the hardware using it. For example, if the computer has a Hayes SmartModem board then OUT1=1 resets the modem.
  • OUT2 – controls interrupt servicing for the UART: OUT2=0 blocks the interrupt generated by the UART. This allows the user to prevent UART interrupts from reaching the computer’s priority interrupt controller, while still generating them within the UART.
  • CTS (Clear to Send) – This signal is asserted (logic ‘0’, positive voltage) by the DCE device to inform the DTE device that transmission may begin. RTS and CTS are commonly used as handshaking signals to moderate the flow of data into the DCE device.
  • DSR (DCE Ready) – When originating from a modem, this signal is asserted (logic ‘0’, positive voltage) when the following three conditions are all satisfied:
    • The modem is connected to an active telephone line that is “off-hook”
    • The modem is in data mode, not voice or dialing mode
    • The modem has completed dialing or call setup functions and is generating an answer tone
  • DCD (Carrier Detect) – This signal is relevant when the DCE device is a modem. It is asserted (logic ‘0’, positive voltage) by the modem when the telephone line is “off-hook”, a connection has been established, and an answer tone is being received from the remote modem. The signal is deasserted when no answer tone is being received, or when the answer tone is of inadequate quality to meet the local modem’s requirements (perhaps due to a noisy channel).
  • RI (Ring Indicator) – his signal is relevant when the DCE device is a modem, and is asserted (logic ‘0’, positive voltage) when a ringing signal is being received from the telephone line. The assertion time of this signal will approximately equal the duration of the ring signal, and it will be deasserted between rings or when no ringing is present.
  • DTE (Data Terminal Equipment) is a computer or terminal and has a male serial port connector attached.
  • DCE (Data Circuit-terminating Equipment) is a modem with female serial port attached.