The null modem cable with full handshaking does not permit the older way of flow control to take place. The main incompatibility is the cross connection of the RTS and CTS pins.

Jun 13, 2015 · Or, since most PCs these days don't require flow control, it can be called a null-modem cable. Your documentation is being correct by specifying a three-wire cable, but a full-up null-modem would also work.

Apr 27, 2009 · The simple null modem cable and the null modem cable with loop back handshaking are useful, but have no provisions for hardware flow control. If it is absolutely necessary that hardware flow control is used, the null modem with partial handshaking can …

Apr 4, 2019 · Null modem cables changed that old standard, allowing devices to be linked up directly with no middleman equipment. This allows older computers and other machines with serial ports to transfer data between each other directly, similar to more modern ethernet crossover cables.

Dec 28, 2018 · In the Loop Back Hand Shaking, the cable pin merely loops back and does not physically support the hardware flow control due to compatibility issues and potential problems with a simple null modem cable. In Partial Hand Shaking, the flow control cable lines are still looped back into the device.

Dec 13, 2009 · DTR/DSR and RTS/CTS are shorted in each side, to make "fake" signals and allow you to use hardware flow control with only three wires. This cable can work on most computers, but it can easily run into trouble (so you'll have to switch to software flow control).

The purpose of a null-modem cable is to permit two RS-232 "DTE" devices to communicate with each other without modems or other communication devices (i.e., "DCE"s) between them.

This type of communication can be performed with a null modem cable for full handshaking. Although using this cable is not completely compatible with the original way hardware flow control was designed, if software is properly designed for it it can achieve the highest possible speed because no overhead is present for requesting on the RTS line ...

Sep 3, 2009 · The simple null modem cable and the null modem cable with loop back handshaking are useful, but have no provisions for hardware flow control. If it is absolutely necessary that hardware flow control is used, the null modem with partial handshaking can …

DTE normally refers to the serial port on a PC or terminal, while DCE refers to a modem or other type of communications device. Depending on the type of device on each end of the line, you either need a straight-through or a null-modem ("crossover") cable in order to communicate.