#Epson serial cable pinout db9 to db9 serial

Serial communication devices make use of 9 or 25 pin D-type connectors for their cabled connections. The RS protocol specifies the operation mode, electrical standards, number of bits, and voltage levels to be used when transferring data between a DTE and DCE. The basic example of these two types of equipment defines a computer as a DTE device with a modem filling the role of DCE. Distances of up to 20 meters are the limit for reliable data transfer using the RS interface. The RS protocol transmits data of wires employing signal levels that differ from the standard 5V in order to minimize signal interference. We will take a look at the serial port pinouts used to implement RS as well as some additional reference information concerning the protocol. Latest posts by Reza Mousavi see all.The RS protocol is a popular serial interface that is used to connect computers to peripheral devices such as modems. Set when incoming ring detected - used for auto-answer application.ДЄuthor Recent Posts. DCE Modem raises when incoming call detected used for auto answer applications. The male connector has the pins sticking out! Only needed if second channel being used. Some manufacturers mark each pin number on the plastic housing at the rear of the connector. Generally Pin 1 is marked on the front of the connector right next to the pin - though you may need a magnifying glass to read it. These diagrams show the male grey background and female black background pin numbering for DB9 and DB25 sub-miniature connectors. This is called a NULL no modem configuration. When PCs are connected back-to-back each end is acting as a DTE there is no DCE in this case and consequently certain signals may have to be looped in the connection to satisfy any input signal requirement. RS defines both the physical and electrical characteristics of the interface.