Description. Serial Port Splitter is a program in which the user can transfer data simultaneously from many communications applications to one COM port. It is to avoid data transfer errors. Key features. Virtual serial ports: The software allows the splitting of one physical COM port into various virtual.. Описание: Serial Port Splitter - Share dataflow of one serial port among several applications or join dataflow of several serial port devices to one application. Color Scheme. Serial Port Splitter- позволяет совместное использование последовательного порта несколькими приложениями одновременно. Программа создает виртуальные COM-порты, являющиеся точными копиями заданного физического COM-порта..
Interfacing The Serial / RS- 2. Port. Interfacing the Serial / RS2. Port. The Serial Port is harder to interface than the Parallel Port.
In most cases. any device you connect to the serial port will need the serial transmission. This can be done using a.
UART. On the software side of things, there are many more registers that you. Standard Parallel Port. SPP). So what are the advantages of using serial data transfer rather than parallel? Serial Cables can be longer than Parallel cables. The serial port transmits a '1' as - 3 to - 2. Therefore the serial port can have a maximum swing of 5.
V compared to the parallel port which has a maximum swing of 5 Volts. Therefore cable loss is not going to be as much of a problem for serial cables than they are for parallel. You don't need as many wires than parallel transmission. If your device needs to be mounted a far distance away from the computer then 3 core cable (Null Modem Configuration) is going to be a lot cheaper that running 1.
However you must take into account the cost of the interfacing at each end. Infra Red devices have proven quite popular recently.
You may of seen many electronic diaries and palmtop computers which have infra red capabilities build in. However could you imagine transmitting 8 bits of data at the one time across the room and being able to (from the devices point of view) decipher which bits are which? Therefore serial transmission is used where one bit is sent at a time. Ir. DA- 1 (The first infra red specifications) was capable of 1. UART. The pulse length however was cut down to 3/1.
RS2. 32 bit length to conserve power considering these devices are mainly used on diaries, laptops and palmtops. Microcontroller's have also proven to be quite popular recently. Many of. these have in built SCI (Serial Communications Interfaces) which can be.
Serial Communication reduces the pin. MPU's. Only two pins are commonly used, Transmit Data (TXD). Receive Data (RXD) compared with at least 8 pins if you use a 8 bit. Parallel method (You may also require a Strobe).
Above is my preferred method of wiring a Null Modem. It only requires 3 wires. TD, RD & SG) to be wired straight through thus is more cost effective to. The theory of operation is reasonably easy. The. aim is to make to computer think it is talking to a modem rather than.
Any data transmitted from the first computer must be. TD is connected to RD. The second computer.
RD is connected to TD. Signal Ground (SG). The Data Terminal Ready is looped back to Data Set Ready and Carrier Detect. When the Data Terminal Ready is asserted active, then the. Data Set Ready and Carrier Detect immediately become active.
Соединения со счетчиком использовались пробные версии разнообразных программ, которые называются Serial Port Splitter. . Does anyone know how I can split a serial cable so the output from one device is connected as inputs to two different computers? With our serial port splitters you gain reliability by capturing data from one peripheral on redundant PCs. By allowing you to share multiple PCs on a single .
At this point. the computer thinks the Virtual Modem to which it is connected is ready and. All left to worry about now is the Request to Send and Clear To Send. As. both computers communicate together at the same speed, flow control is not. When. the computer wishes to send data, it asserts the Request to Send high and. Clear to Send, It immediately gets a reply.
Notice that the ring indicator is not connected to anything of each end. This line is only used to tell the computer that there is a ringing signal. As we don't have a modem connected to the phone line this.
Figure 2 : Loopback Plug Wiring Diagram. This loopback plug can come in extremely handy when writing Serial / RS2. Communications Programs.
It has the receive and transmit lines connected. Serial Port is. immediately received by the same port. If you connect this to a Serial Port. Terminal Program, anything you type will be immediately displayed.
This can be used with the examples later in this tutorial. Please note that this is not intended for use with Diagnostic Programs and. For these programs you require a differently. Loop Back plug which may vary from program to program. We have already talked briefly about DTE & DCE. A typical Data Terminal. Device is a computer and a typical Data Communications Device is a Modem.
Often people will talk about DTE to DCE or DCE to DCE speeds. DTE to DCE is. the speed between your modem and computer, sometimes referred to as your. This should run at faster speeds than the DCE to DCE speed. DCE to DCE is the link between modems, sometimes called the line speed.
Most people today will have 2. K or 3. 3. 6. K modems. Therefore we should. DCE to DCE speed to be either 2. K or 3. 3. 6. K. Considering the. DTE to DCE speed to be.
BPS.(Maximum Speed of the 1. UART) This is where some. The communications program. DCE to DTE speeds. However they see 9.
KBPS, 1. 4. 4 KBPS etc and think it is your modem speed. Today's Modems should have Data Compression build into them. This is very. much like PK- ZIP but the software in your modem compresses and decompresses.
When set up correctly you can expect compression ratios of 1: 4 or. If we were. transferring that text file at 2. K (DCE- DCE), then when the modem. KBPS between computers and.
DCE- DTE speed of 1. KBPS. Thus this is why the DCE- DTE should.
Some modem manufacturers quote a maximum compression ratio as 1: 8. Lets say. for example its on a new 3. KBPS modem then we may get a maximum 2.
BPS transfer between modem and UART. If you only have a 1. BPS tops, then you would be missing out on a extra bit of. Buying a 1. 6C6. 50 should fix your problem with a maximum transfer. BPS. However don't abuse your modem if you don't get these rates. These are. MAXIMUM compression ratios.
In some instances if you try to send a already. If this. occurs try turning. This should be fixed on newer modems.
Some files. compress easier than others thus any file which compresses easier is. So if our DTE to DCE speed is several times faster than our DCE to DCE speed. PC can send data to your modem at 1. BPS. Sooner or later data is. Flow control has two basic. Hardware or Software. Software flow control, sometimes expressed as Xon/Xoff uses two characters.
Xon and Xoff. Xon is normally indicated by the ASCII 1. ASCII 1. 9 character is used for Xoff. The modem will only have a small. Xoff character to. Once the modem has room for more. Xon character and the computer sends more data.
This. type of flow control has the advantage that it doesn't require any more. TD/RD lines. However on slow links. Hardware flow control is also known as RTS/CTS flow control. It uses two. wires in your serial cable rather than extra characters transmitted in your. Thus hardware flow control will not slow down transmission times. Xon- Xoff does. When the computer wishes to send data it takes active. Request to Send line.
If the modem has room for this data, then the. Clear to Send line and the computer. If the modem does not have the room then it will not. Clear to Send. UART stands for Universal Asynchronous Receiver / Transmitter. Its the little. box of tricks found on your serial card which plays the little games with. Most cards will have the UART's.
The 8. 25. 0 series, which includes the 1. UARTS are the most commonly found type in your PC.
Later we will look at. Figure 3 : Pin Diagrams for 1. UARTs. The 1. 65. The only two differences. On the 8. 25. 0 Pin 2. Pin 2. 9 was not.
UARTs. The 1. 65. These are Transmit Ready. Receive Ready which can be implemented with DMA (Direct Memory Access). These Pins have two different modes of operation.
Mode 0 supports single. DMA where as Mode 1 supports Multi- transfer DMA. Mode 0 is also called the 1.
This mode is selected when the FIFO. Bit 0 of the FIFO Control Register or When the. FIFO buffers are enabled but DMA Mode Select = 0. Bit 3 of FCR) In this. RXRDY is active low when at least one character (Byte) is present in. Receiver Buffer. RXRDY will go inactive high when no more characters are. Receiver Buffer. TXRDY will be active low when there are no.
Transmit Buffer. It will go inactive high after the. Transmit Buffer. Mode 1 is when the FIFO buffers are active and the DMA Mode Select = 1. In. Mode 1, RXRDY will go active low when the trigger level is reached or when. Time Out occurs and will return to inactive state when no more. FIFO. TXRDY will be active when no characters. Transmit Buffer and will go inactive when the FIFO. Transmit Buffer is completely Full.
All the UARTs pins are TTL compatible. That includes TD, RD, RI, DCD, DSR. CTS, DTR and RTS which all interface into your serial plug, typically a.
D- type connector. Therefore RS2. 32 Level Converters (which we talk about in.
These are commonly the DS1. Receiver and the DS1. PC has +1. 2 and - 1. The. RS2. 32 Converters will convert the TTL signal into RS2.
Logic Levels. Pin No. Name. Notes. Pin 1: 8. D0: D7. Data Bus. Pin 9. RCLKReceiver Clock Input.
The frequency of this input should equal the receivers baud rate * 1. Pin 1. 0RDReceive Data. Pin 1. 1TDTransmit Data. Pin 1. 2CS0. Chip Select 0 - Active High. Pin 1. 3CS1. Chip Select 1 - Active High. Pin 1. 4n. CS2. Chip Select 2 - Active Low.
Pin 1. 5n. BAUDOUTBaud Output - Output from Programmable Baud Rate Generator. Frequency = (Baud Rate x 1. Pin 1. 6XINExternal Crystal Input - Used for Baud Rate Generator Oscillator. Pin 1. 7XOUTExternal Crystal Output. Pin 1. 8n. WRWrite Line - Inverted. Pin 1. 9WRWrite Line - Not Inverted.
Pin 2. 0VSSConnected to Common Ground. Pin 2. 1RDRead Line - Inverted. Pin 2. 2n. RDRead Line - Not Inverted. Pin 2. 3DDISDriver Disable. This pin goes low when CPU is reading from UART.
Can be connected to Bus Transceiver in case of high capacity data bus. Pin 2. 4n. TXRDYTransmit Ready.
Pin 2. 5n. ADSAddress Strobe. Used if signals are not stable during read or write cycle.
Pin 2. 6A2. Address Bit 2. Pin 2. 7A1. Address Bit 1. Pin 2. 8A0. Address Bit 0. Pin 2. 9n. RXRDYReceive Ready. Pin 3. 0INTRInterrupt Output.
Pin 3. 1n. OUT2. User Output 2. Pin 3. 2n. RTSRequest to Send. Pin 3. 3n. DTRData Terminal Ready. Pin 3. 4n. OUT1. User Output 1. Pin 3. 5MRMaster Reset. Pin 3. 6n. CTSClear To Send.
Pin 3. 7n. DSRData Set Ready. Pin 3. 8n. DCDData Carrier Detect. Pin 3. 9n. RIRing Indicator. Pin 4. 0VDD+ 5 Volts. Table 2 : Pin Assignments for 1. A UART. The UART requires a Clock to run.
If you look at your serial card a. MHZ or a 1. 8. 4.