Ethernet is packetized, you literally can not send a single valid byte as there is a pile of addressing, CRC, etc. So, Ethernet can communicate in Serial. A 10-base-T Ethernet connection sends individual bits in sequence, but higher-speed cabling often uses various signalling methods to send multiple bits at once.
Following are the benefits or advantages of Serial Interface: ➨It uses less number of conducting wires, hence reduces cost of the interface. ➨It supports long distance data communication. ➨It uses less number of wires often only one, this leads to simple interface between transmitting and receiving devices or ICs.
RS422 was introduced to enable higher data rates to be transferred over serial data lines than was possible with RS232. RS422 is able to provide data rates of up to 10 Mbps at distances up to 50 feet (15.24 metres).
Serial and Parallel are always digital. The device plugged into the end of the cable does at a Digital to Analog or Analog to Digital conversion. Not necessary - the VGA is analog but you can also consider it a "parallel" cable since multiple color are sent over different wires at the same time.
A Serial port is an asynchronous port on the computer used to connect devices serially to the computer. It is a serial communication interface through which port is capable of transmitting one bit at a time. A USB is a standard cable connection interface between personal computers and electronic devices of consumer.
RS232 is a standard protocol used for serial communication, it is used for connecting computer and its peripheral devices to allow serial data exchange between them. As EIA defines, the RS232 is used for connecting Data Transmission Equipment (DTE) and Data Communication Equipment (DCE).
Half duplex means that the device cannot send and receive at the same time. Full duplex serial communication needs at a minimum three wires, signal ground, transmit data line, and receive data line. The RS232 specification governs the physical and electrical characteristics of serial communications.
The main advantage of serial communication is, the cost of the entire embedded system becomes cheap and transmits the information over a long distance. Serial transfer is used in DCE (Data communication Equipment) devices like a modem. In parallel communication, a chunk of data (8,16 or 32 bit) is sent at a time.
RS-485, also known as TIA-485(-A) or EIA-485, is a standard defining the electrical characteristics of drivers and receivers for use in serial communications systems. Electrical signaling is balanced, and multipoint systems are supported.
Cables. Many serial communication systems were originally designed to transfer data over relatively large distances through some sort of data cable. Practically all long-distance communication transmits data one bit at a time, rather than in parallel, because it reduces the cost of the cable.
1. RS232 is full-duplex, RS485 is half-duplex, and RS422 is full-duplex. RS485 and RS232 are only the physical protocol of communication (ie interface standard), RS485 is the differential transmission mode, RS232 is the single-ended transmission mode, but the communication program does not have much difference.
technically, it is all analog (RS-232 uses voltage levels).
SSI (Serial Synchronous Interface) is a widely used serial interface between an absolute position sensor and a controller. SSI uses a clock pulse train from a controller to initiate a gated output from the sensor. Position data is continually updated by the sensor and made available to the shift register.
The biggest difference between RS422 and RS485 is how they communicate with devices on a single pair of differential wires. RS422: Each Bus only offers One-way communication. A single transmitting (master) device to one or more receiving (slave) devices on a single pair of wires.
1. RS232 is full-duplex, RS485 is half-duplex, and RS422 is full-duplex. RS485 and RS232 are only the physical protocol of communication (ie interface standard), RS485 is the differential transmission mode, RS232 is the single-ended transmission mode, but the communication program does not have much difference.
The Serial Port - Software Setup
- Step 1: Find Your Serial Port. In order to set it up, first you have to find it on your computer.
- Step 2: Open Up Hyperterminal.
- Step 3: Enter the Serial Port Info.
- Step 4: Set Connection Parameters.
- Step 5: The Serial Connection - Signals.
- Step 6: Loopback Test.
- Step 7: Start Typing.
- Step 8: Double Echo.
Due to the way the signals are connected, a common ground is required. This implies limited cable length - about 30 to 60 meters maximum. (Main problems are interference and resistance of the cable.) Shortly, RS 232 was designed for communication of local devices, and supports one transmitter and one receiver.
RS-232C. RS-232 stands for Recommend Standard number 232 and C is the latest revision of the standard. The serial ports on most computers use a subset of the RS-232C standard. The full RS-232C standard specifies a 25-pin "D" connector of which 22 pins are used.
USB communication is a serial bus. USB sends data in serial mode i.e. the parallel data is serialized before sends and de-serialized after receiving.
Now if the data is sent in series i.e. one after the other then the communication protocol is known as Serial Communication Protocol. More specifically, the data bits are transmitted one at a time in sequential manner over the data bus or communication channel in Serial Communication.
The serial data format includes one start bit, between five and eight data bits, and one stop bit. The data bits are often referred to as a character because these bits usually represent an ASCII character. The remaining bits are called framing bits because they frame the data bits.
HDMI, DVI, and PCIe are all optionally data parallel. They are all capable of operating with a single serial data channel, though they all have a separate clock signal (though in the case of PCIe it's a reference clock instead of a signal transmission clock).
I2C is a serial protocol for two-wire interface to connect low-speed devices like microcontrollers, EEPROMs, A/D and D/A converters, I/O interfaces and other similar peripherals in embedded systems. It was invented by Philips and now it is used by almost all major IC manufacturers.
When transmitting a byte, the UART (serial port) first sends a START BIT which is a positive voltage (0), followed by the data (general 8 bits, but could be 5, 6, 7, or 8 bits) followed by one or two STOP BITs which is a negative(1) voltage. The sequence is repeated for each byte sent.
Which devices can these ports be found on?
| Port | Desktop | Laptop |
|---|
| DVI | Yes | Yes |
| Parallel | Yes | No |
| Serial | Yes | Yes |
| PS/2 | Yes | No |
The key difference between a serial (or parallel) port on a computer and an Ethernet port is what you're connecting. Ethernet on the other hand is only network connection used for much larger networks permitting other devices and computers to communicate with each other over very long distances.
Modbus is a communication protocol developed by Modicon systems. In simple terms, it is a method used for transmitting information over serial lines between electronic devices. The device requesting the information is called the Modbus Master and the devices supplying information are Modbus Slaves.
