Serial port small ticket printer printing garbled problem

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Editor:yeungchi

Date:2016/3/29

Describe: small ticket printer garbled problem

Article content:
First, the parameter explanation

Second, serial connection printer setup case

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Serial port is a very common protocol for device communication;

First, the parameter explanation

Baud rate This is a parameter that measures the symbol transfer rate. It represents the number of symbols transmitted per second. For example, 300 baud indicates that 300 symbols are sent per second. When we refer to the clock cycle, we refer to the baud rate, for example, if the protocol requires a 4800 baud rate, then the clock is 4800Hz. This means that the sampling rate of the serial communication on the data line is 4800Hz. Usually the baud rate of the telephone line is 14400,28800 and 36600. The baud rate can be much larger than these values, but the baud rate is inversely proportional to the distance. The high baud rate is often used to place very close inter-instrument communication, the typical example being the communication of a GPIB device.   Baud rate Index according to the signal to the carrier modulation rate, it is in the unit time the carrier modulation state changes the number of times to express, its unit is Porter (Baud). The baud rate is related to the bit rate: bit rate = baud rate x the number of bits corresponding to the individual modulation state. Obviously, the bit rate of the two-phase modulation (a single modulation state corresponds to 1 bits) is equal to the baud rate, the bit rate of the four-phase modulation (2 bits for a single modulation state) is twice times the baud rate, and the bit rate of the eight-phase modulation (3 bits for a single modulation state) is three times times the baud rate; RS232 is to be used in close range transmission on the maximum distance of 30mrs485 used over long distances to transmit the maximum distance of 1200M data bits This is the parameter that measures the actual data bits in the communication. When the computer sends a packet, the actual data is not 8-bit, and the standard values are 5, 6, 7, and 8 bits. How to set up depends on the information you want to send. For example, the standard ASCII code is 0~127 (7-bit). The extended ASCII code is 0~255 (8-bit). If the data uses simple text (the standard ASCII code), then each packet uses 7 bits of data. Each package refers to a byte, which includes the start/stop bits, data bits, and parity bits. Since the actual data bit depends on the selection of the communication protocol, the term "package" refers to any communication situation. The stop bit is used to represent the last one in a single package. Typical values are 1, 1.5, and 2 bits. Since the data is timed on the transmission line, and each device has its own clock, it is likely that there is a small difference between the two devices in the communication. So the stop bit is more than just the end of the transmission, and provides the opportunity for the computer to calibrate the clock synchronization. The more bits that apply to the stop bit, the greater the tolerance for different clock synchronizations, but the slower the data transfer rate. Parity bit is a simple method of error detection in serial communication. There are four methods of error detection: Occasional, odd, high and low. Of course, no check bit is also possible. For even and odd checks, the serial port sets the check bit (one after the data bit), using a value to ensure that the transmitted data has an even or odd logical high. For example, if the data is 011, for parity, the check bit is 0, and the number of bits that are logically high is an even number. If it is a parity check, the check bit is 1, so there are 3 logical highs. Highs and lows are not reallyCheck data, simple bit logic high or logic low. This allows the receiving device to know the state of a bit, the opportunity to determine whether there is noise interfering with the communication or whether the transmission and reception of the data is not synchronized.    second, serial connection printer setup caseProblem: Small ticket printer printing garbled analysis: 1. Bad data line; 2. The baud rate of the port setting is not synchronized with the small ticket printer baud rate; Solution: Problem 1 is easy to solve, replace the data cable and reproduce the data cable. For issue 2, by viewing the booklet of the Small ticket printer can set the baud rate of the small ticket printer; finally through the help of the manual, the DIP switch in the SW-7 open (factory set is off, the default 19200) solves the problem of printing garbled; add: The following is the degree Niang answer

Typical performance: The printer suddenly print a few lines of garbled, and then do not work.
Workaround: For ordinary users, sometimes restarting the system (computer, printer) is the simplest way to solve the problem.

However, we sometimes find that after restarting the printer, the printer is strangely followed by a garbled print. At this point, the print job has disappeared in Print Manager.
In fact, the print job still exists, but the computer's CPU after processing it is stored on the hard disk, the hard disk directly through the memory sent to the printer.
In other words, the job is still on the hard drive.
This time we need to do more work: please click on "Control Panel"-"Administrative Tools"-"services".
Then open the list of services, select the "Print Spooler" service in the list of Windows services, and abort the service.

2, data transmission problems.
Because of the false welding or interface circuit, chip failure, the data can be lost in transmission, resulting in garbled printing, Chinese character printing errors and other failures.
The same port cable remember not to plug and unplug, otherwise the pin is easy to short-circuit, the interface chip is easily burned by the inrush current. Never be lucky.
Typical phenomenon: Sometimes we feel strange, after sending the print job everything is OK, the printer starts to work the Hula啦 from the beginning to the tail, looks also very normal.
But the printed things are messy, garbled, dislocation, missing and other phenomena have been presented.
WORKAROUND: First let the printer do a self-test (see the operating manual for the product), if the self-test page is completely normal,
And you confirm that your computer is not a problem (no virus, printing with other software is the same phenomenon,
Even in start-settings-printers-Select model-Right-click-General under "Print test Page",
We're going to consider the data transfer problem. That is, two ports (computer and printer interface circuit) a line (the same port, serial, USB cable).
Finding a reliable replacement cable is the simplest and most effective. If it is a port problem, it is more troublesome.
3, the printer hardware failure caused by processing data errors.
Printer's font ROM, chip and other components damaged. In addition to the use of the old age, machine natural aging, the cause of printer hardware damage is mainly due to poor working environment.
There is a clear description of the use of the environment in the Epson Printer's manual, but the user really reads it carefully and obeys it very little. There are often users who indicate that their printers work in a very good environment,
But the repairman turned on the printer and found something inside that could open a grocery store. High temperature change, humidity, voltage instability, power supply is not a good grounding in the workplace,
In particular, it can cause damage to the printer. Typical failure: After printing garbled or other symptoms, we can try to do the self-test of the printer.
If there is a self-test page is garbled, or Latin, the number is normal, Chinese alone, or not at all, is the printer itself hardware failure.
WORKAROUND: Please contact Epson's Repair station as soon as possible. The maintenance staff will carefully and specifically inspect your printer.
4, the software emulation mode and the printer driver do not match. Epson's PIN printers can also simulate some other manufacturers ' printers to work.
Like the simulation of Oki's and IBM's. At this point the equivalent of a OKI or IBM printer is working, then of course we have to install the appropriate OKI or IBM printer driver.
There are often users who choose the current emulation of the printer firmware as OKI or IBM, but the driver for the Epson printer is installed on the computer. As a result, printing will appear garbled and other phenomena.
5. When the serial port is connected, the baud rate setting does not match the baud rate device of the connected device.
The printer with serial card installed (see the operating manual), the factory usually set the baud rate to 9600, which is the same as the default baud rate of the computer serial port.
But many use the serial port to connect the printer's industrial control equipment, the measuring instrument, because emphasizes the stability but does not require the transmission speed, the serial port baud rate basically defaults to 1200 low value.
This way, if you do not make adjustments to start online printing, printing will appear garbled.
In addition: sometimes even if the printer and the computer's serial port set the same baud rate,
May still be due to the processing speed mismatch (of course, the computer fast printer slow), so that the printer buffer overflow, the printer CPU response is not in time, can also cause printing garbled or other problems.
At this time, we also need to manually put the printer and the computer serial baud rate is also reduced. For example, reduce from 9600 to 4800 at the same time.
However, the baud rate of the computer and printer must be the same, which should be adhered to at any time.
Please note: In some of the serial card as an option of the printer products, the serial card before installation, the default settings list is no baud rate of this item.
The key is automatically generated when the serial card is installed. Other printers have a hard jumper on the serial card that sets the baud rate. You can change the baud rate directly with the jumper.
Workaround: The default settings table for the printer or the location of the jumper shows the baud rate value of the current serial port setting.
For those serial cards that need to change the baud rate using the buttons in the printer panel in the default settings, we need to print the vacancy Provincial Settings page and change the serial baud rate as indicated above.
You can follow the steps step by step to change the baud rate of the printer to the same device serial baud rate value.
For those serial cards that use a hard jumper to change the baud rate, please refer to the Baud rate table on the serial card's user manual for modification.

Serial port small ticket printer printing garbled problem