The software offers three different options for setting signal lines pinout:
- Standard is the default serial port pinout for serial communications with partial handshaking.
- Loopback Mode allows virtual COM ports communicate using RS232 loopback handshaking.
- Custom COM port pinout preset can be selected and saved by a user in the software settings.
Standard RS-232 null modem pinout preset scheme:
Loopback mode pinout preset scheme:
To set Custom serial connector pinout:
- Go to the ’Custom pinout’ tab.
- In the Serial Ports Explorer choose the required virtual COM port pair.
- Select the lines for the ‘IN’ side of the pair and connect them to the required ‘OUT’ side lines by checking the corresponding boxes.
- Name the preset and click the ’Save preset’ button.
There are two types of devices involved in serial communication: DTE (Data Terminal Equipment) - a controller of serial connection, computer that fits a male serial port connector, and DCE (Data Circuit-terminating Equipment) - a modem with a female COM port connector.
Data on RS-232 is normally sent using signal lines, which have the following meanings:
RTS (Request to Send) – request for data exchange indicating that the data set is ready to send information to the DTE;
CTS (Clear to Send) – a positive voltage signal indicating that a modem is able to receive data from the data terminal and that the DTE can start data transfer.
DTR (DTE Ready) – a signal sent from the DTE to a modem or other device to indicate that the serial port controller (UART) is prepared to establish a connection;
DSR (DCE Ready) – a signal sent from a modem to the data terminal to indicate that the modem is turned on, initialized, and prepared to communicate with the computer.
DCD (Data Carrier Detect) – a signal sent from the DCE to the DTE to indicate that the DCE is connected to a distant modem. Logic ’0′ means that the communication between the modems is active.
RI (Ring Indicator) – a signal sent from a modem to a computer to indicate that the DCE device (the modem) is receiving a ringing signal from the telephone line.