What is Null Modem cable?
Null Modem cable is regularly called a crossover cable . It is utilized to permit two serial Data Terminal Equipment (DTE) gadgets to speak with each other without utilizing a modem or a Data Communications Equipment (DCE) gadget in the middle. For this to happen, the Transmit (TXD) stick of one gadget should be associated with the Receive (RXD) stick of the other gadget. To empower handshaking between the two gadgets, the Request to Send (RTS) stick of one gadget must be associated with the Clear to Send (CTS) stick of the other gadget. Since these pins are "crossed" on the two link terminals, the name crossover cable is utilized.
How to emulate null-modem cable?
In the event that there is a necessity to catch serial information from another application on a similar PC, the Null Modem Emulator might be introduced. This gives connected sets of virtual serial ports, ie COM21 is connected to COM22, so any information sent to COM21 touches base at COM22. This abstains from expecting to utilize a couple of physical ports and an invalid modem link. It may be utilized for catching serial printer information.
The Virtual Null-modem emulator is the virtual serial port driver for Windows. You can create an unlimited number of virtual COM port pairs and use any pair to connect one application to another. Each COM port pair provides two COM ports with default names starting
at CNCA0 and CNCB0. The output to one port is the input from other port and vice versa.