The RS interface presupposes a common ground between the DTE and DCE The types of driver ICs used in serial ports can be divided into three general. Officially, RS is defined as the "Interface between data terminal equipment and data communications equipment using serial binary data exchange. In telecommunications, RS, Recommended Standard is a standard introduced in for serial communication transmission of data. It formally defines  ‎Scope of the standard · ‎History · ‎Physical interface · ‎Data and control signals.


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After a connection has been made the modem will be connected to the line by using DTR. This connection will remain until the terminal is switched rs232 serial interface line when the DTR line is dropped. The modem will detect this and release the telephone line. Sometimes pin 20 is not assigned to DTR.

RS - RS - Serial port - Telecom ABC

This is virtually the same as DTR, but differs in that DTR merely enables the modem to be switched onto the telephone line. CDSTL commands the modem rs232 serial interface switch, despite anything else it may be doing.

This pair of circuits are used together. The terminal equipment will flag that it has data to send.

RS Tutorial on Data Interface and cables

The modem will then return the CTS signal to give the all clear after a short delay. This signalling is used particularly when switched carriers are used. It means that the carrier is only present on the line when there is data to send. It finds its uses when one central rs232 serial interface is servicing several others at remote locations.

Secondary lines There are two types of lines that are specified in the RS specification. There are the primary channels that rs232 serial interface normally used, and operate at the normal or higher data rates.

However, there is rs232 serial interface provision for a secondary channel for providing control information. If it is used it will usually send data at a much slower rate than the primary channel.

As the secondary lines are rarely used or even implemented on equipment, manufacturers rs232 serial interface use these connector pins for other purposes.

RS232 Serial Interface: V24

The standards to kbps or less and line lengths of 15M 50 ft or less but today we see high speed ports on our home PC running very high speeds rs232 serial interface with high quality cable maxim distance has increased greatly.

The rule of thumb for the length a data cable depends on speed of the data, quality of the cable.


RS single-ended was introduced inand despite rumors for its early demise, has remained widely used through the industry. Independent channels are established for two-way full-duplex communications.

RS has numerous handshaking lines primarily used with modemsrs232 serial interface also specifies a communications protocol. This is a reasonable assumption when a short cable connects the DTE to the Rs232 serial interface, but with longer lines and connections between devices that may be on different electrical busses with different grounds, this may not be true.

The RS-232 protocol

rs232 serial interface RS data is bi-polar Modern computer equipment ignores the negative level and accepts a zero rs232 serial interface level as the "OFF" state. In fact, the "ON" state may be achieved with lesser positive potential.

For many years, an RScompatible port was a standard feature for serial communicationssuch as modem connections, on many computers with the computer acting as the DTE.

It remained in widespread use into the late s.

In personal computer peripherals, it has largely been supplanted by other interface standards, such as USB. RS is still used to connect older designs of peripherals, industrial equipment such as PLCsconsole ports, and special purpose equipment.

Revision D was issued in rs232 serial interface Issues with the RS standard include: The voltage swing requirement also limits the upper speed of a rs232 serial interface interface. Single-ended signaling referred to a common signal ground limits the noise immunity and transmission distance.