EntranceHow to make a null modem cable for flashing receivers yourself. Null modem cable (RS232) pinout Null modem
About RS-232 (wiring cables, connectors, brief description)
RS-232C contacts
Wiring the "modem" RS-232C interface cable
Communication and RS-232 interface
Troubleshooting RS-232 Communications
RS-232C contacts
RS-232C interface DB-9 connector pins
Wiring the "modem" RS-232C interface cable
Wiring the Null Modem RS-232C Interface Cable
RS-232C Cable Wiring for Kramer Switches
Communication and RS-232 interface
When working in potentially noisy environments, we need a reliable means of transmitting data. The most common standard is still the archaic RS-232C (Recommended Standard 232 Version C), adopted by the Electronic Industries Association (EIA) in August 1969.
Advantages of RS-232:
Popularity - all PCs (but not Macs) are equipped with at least one RS-232 port
Ease of acquiring ready-made cables
Ability to use hardware control of the transfer process (often not used!)
Disadvantages of RS-232:
Point-to-Point Communication (DTE? DCE)
Low, by today's standards, speed (typically 9600 baud [bits per second])
Works only on short distances(up to 10 m)
The composition of the communication lines between DTE and DCE devices is not precisely defined. The standard describes the functions of up to 25 trunks, but does not specify whether a particular trunk should or should not be used. Things are better (technologically) in the RS-422 standard. According to this standard, communication is carried out over two pairs of wires, and the transmitted signal can be received by more than one device. The RS-485 standard (improved RS-422) uses a single pair of wires that is used to transmit or receive by many devices.
Features and benefits of RS-422/RS-485:
Can be used for multipoint connections
It is the de facto standard for much of the broadcast video industry!
Can be used at distances up to 1.2 km
High noise immunity due to the use of differential (balanced) communication lines
KRAMER VP-43 Range Extender:
Designed to overcome distance limitations for our RS-232 controlled products.
Converts to RS-422 and then back to RS-232, allowing two pairs of wires to be used as physical media.
Can be used to extend the communication distance for any null modem RS-232 connection.
It can also be used to control our products via RS-422, or as a general purpose converter from RS-232 to RS-422 and vice versa.
Port Extender KRAMER VP-14 Port Extender:
Designed to overcome the limitation of the RS-232 interface, which can only make point-to-point connections. Allows communication between multiple devices with RS-232 interfaces.
Data that arrives at any of the ports of the device is sent to the other 3 ports.
Can be used to control the switch from 3 DTE devices (eg computers).
Works in all communication modes (number of bits, speed, parity, etc.) and does not require setting these parameters.
Troubleshooting RS-232 Communications
The following are steps that can help resolve problems when communicating with Kramer devices via the RS-232 interface.
1. Make sure that a null modem connection is established between the device (switch, router) and the host computer (PC).
The easiest way (when using the 25-pin port on the PC) is to use the null modem adapter that came with the device. Connect such an adapter with a 25-pin connector to the serial port of the PC, then use a straight cable - that is, one-to-one soldering - connect the 9-pin connector of the adapter to the serial port on the device. (If the adapter is used with a partial cable, then at least a 9-pin connector must be connected at both ends: pin 2 to pin 2, 3 to 3 and 5 to 5.)
When directly connecting the 25-pin port on the PC to the 9-pin connector on the device (i.e. without a null modem adapter), connect the following:
Pin 2 on 25-pin connector - with pin 2 on 9-pin
Pin 3 on a 25-pin connector - with pin 3 on a 9-pin
Pin 7 on a 25-pin connector - with pin 5 on a 9-pin
Short together pins 6 and 20 on the 25-pin connector
Short together pins 4, 5 and 8 on the 25-pin connector
When directly connecting the 9-pin port on the PC to the 9-pin connector on the device, connect the following:
Pin 2 on the PC connector - with pin 3 on the device connector
Pin 3 on the PC connector - with pin 2 on the device connector
Pin 5 on the PC connector - with pin 5 on the device connector
Short together pins 4 and 6 on the PC connector
Short together pins 1, 7 and 8 on the PC connector
2. Make sure all DIP switches are set correctly on the device.
3. Make sure the baud rate settings on the PC and the device are the same, and the correct COM port is selected on the PC.
4. If multiple devices are being used at the same time, make sure they are all turned on. If any of the devices is turned off in a master/slave system, the exchange in such a system will not be reliable.
5. If the device has a "DISABLE TXD" function, make sure that this function is disabled; similarly, if a DIP switch is used to "disable response", make sure that response is enabled.
6. Pin 3 on the RS-232 connector of the device is used to send data to the PC (this is the TXD of the device and RXD on the PC). Pin 2 on the device connector is used to receive data from the PC (this is the RXD of the device and TXD on the PC). It may be useful to use a digital storage oscilloscope to verify that the device is transmitting/receiving data on specified contacts.
7. Most devices use a "bidirectional" communication protocol. This means that the same code is used both to send a command to the device to perform a certain action, and as a response from the device (on the PC) when a button on its front panel is pressed to perform a similar action. For example, if the user pressed the buttons and switched input 4 to output 5, the device sends the hex code 7B to the computer; at the same time, when the device receives code 7B, it will also work out the connection of input 4 to output 5. For such a protocol, it may be useful to analyze the codes sent by the device when pressing the buttons on its front panel in order to understand the exchange protocol.
8. When troubleshooting, it may be helpful to use a communication program like Procomm or Viewcom to first analyze the codes sent by the device. Then you can try to send such codes back (see point 7), checking that the device responds to them correctly. Finally, you can send a code by which the device will return its state.
9. If a user-written program is to be used, first check with a proprietary program, if possible, that the communication between the PC and the device is working properly.
10. For equipment that has RS-232 control as an option and is introduced by installing an optional hardware board, check that the board is properly installed (as described in the manual). In particular, for the X02 switch series, check the direct cable connected to the module and make sure that there are no jammed pins on the connectors.
11. Some devices may be controlled by other pieces of equipment and may be configured to operate via RS-232 with such equipment rather than with a computer. In this case, you must correctly configure the device. For example, models BC-2216 and BC-2616 (matrix switchers sound signals 16X16) are factory-configured (default) to work with the BC-2516 (16X16 video matrix switcher). In this case, the sound matrix receives control from the PC through the video matrix. If the sound matrix is to be controlled independently, it must be reconfigured accordingly (to operate as an audio-only switching device).
12. If you need to send several commands, then before sending an additional command, make sure that the device has completed the previous command. To do this, wait for a response to the previous command before sending the next one.
13. Make sure the real RS-232 interface is used to communicate with the device! Some equipment (such as the standard Macintosh serial port), although similar to RS-232, uses different communication modes.
14. When using a PC running Windows NT4.0 (and below), additional precautions must be taken. This system does not have a "plug and play" function, and therefore setting up computer ports in it is not an easy task. See your Windows NT documentation! Even if your program is running on a computer with a different operating system, it is possible that under Windows NT the port will not initialize correctly.
15. Please note that the working distance for RS-232 (by definition) does not exceed 10 meters! If a longer link length is required, our VP-43 "link extender" should be used.
16. By definition, the RS-232 interface is designed to exchange between 2 ports (in our case, this is a PC and a switch). If you need to connect several devices with RS-232 interfaces together, you can use VP-14 (for example, if you need to control the switch from 2 computers and a BC-2000 controller).
(NOTE: For some products in our range, it is possible to control several of these devices when they are connected in series with straight cables - which seems wrong in the light of the above! In fact, we configure the devices in master / slave modes (master / slave), while Only one device, the master device, is connected to the computer via RS-232.With this inclusion, the master device transmits information to and from the PC to the slave devices, and the ports are connected in pairs by the RS-232 interface.)
Almost every computer is equipped with at least one asynchronous serial adapter. Usually it is a separate board that is inserted into the computer's expansion slot or is located directly on the motherboard (system) board.
The asynchronous serial adapter is also referred to as the RS-232-C asynchronous adapter, or RS-232-C port. Each asynchronous adapter usually contains several RS-232-C ports through which various external devices can be connected to the computer. Each such port has several registers through which the program accesses it, and a specific IRQ number to signal the computer about a change in the state of the port. During the BIOS boot procedure, all RS-232-C ports are assigned the logical names COM1 - COM4 (COM port number 1 - 4).
7.1. What are asynchronous I/O ports for?
The serial port is very widely used. That's far from full list applications:
- mouse connection;
- connection of plotters (plotters), scanners, printers, digitizers;
- communication of two computers through serial data ports using a special cable (null modem);
- connection of modems for data transmission over telephone lines;
- connection to a network of personal computers.
7.2. What are the technical parameters of the RS-232-C interface
When transmitting data over long distances without the use of special equipment, due to interference induced by electromagnetic fields, errors may occur. As a result, restrictions are imposed on the length of the connecting cable between devices connected using the RS-232-C interface.
The length limit for the RS-232-C connection cable is 15.24 meters. However, in practice this distance can be much larger. It directly depends on the data transfer rate. According to McNamara (Technical Aspects of Data Communications, Digital Press, 1982) the following values are defined:
The voltage levels on the connector lines are -15..-3 volts for a logical zero, +3..+15 volts for a logical one. The interval from -3 to +3 volts corresponds to an undefined value.
If you connect external devices to the RS-232-C interface connector (and also when connecting two computers with a null modem), first turn off external device and computer, and discharge static electricity (by connecting ground). Otherwise, you can damage the asynchronous adapter.
7.3. What are asynchronous adapters
The asynchronous serial adapter uses a universal asynchronous transceiver chip - UART 8250. The UART 8250 chip in its original form was used only in older models of asynchronous serial adapters. Currently, more modern transceiver chips are used - UART 16450, 16550 and 16550A.
These UART chips, made according to new technology, allow you to achieve a higher data exchange rate, and also have new hardware capabilities. We list the main characteristics of various UART chips, and therefore asynchronous serial adapters on which these chips are installed:
| Chip type UART | Characteristics |
| 8250 (8250-B) | Used on the first IBM PC/XT models, has low performance |
| 16450/(8250-A) | The 16450 chip is almost identical to the 8250. It eliminates errors in the interrupt enable register and adds the ability to put the OUT2 line in a high-impedance state |
| 16550 | Added the possibility of internal buffering of transmitted and received data. Buffers are made in the form of a queue (FIFO). Due to an error in the chip, it is better not to use the buffering feature - you can lose individual characters. In general, the 16550 chip is faster than the 16450. The 16550 chip allows you to use several direct access channels (DMA channels) |
| 16550A (16550AN) | According to its characteristics, it corresponds to 16550, but FIFO implementation errors have been fixed in it. This chip allows programs to use several channels of direct access (DMA channels). If you wish to operate at speeds greater than 9600 baud, you should preferably use an asynchronous serial adapter containing this chip. |
7.4. What is a null modem
If you have two computers equipped with asynchronous serial adapters, you can connect them using a null modem cable. Zero- modem cable connects to the serial adapter ports of connected computers.
With the help of a special software Through a null modem cable, data can be quickly copied between computers. If the computers are not connected to a local network and you need to transfer a large amount of information from one computer to another, using a null modem is the best solution.
A null modem is a fairly simple device. It consists of two connectors and a cable connected in a certain way. If you have two mating connectors from the asynchronous adapter ports and a multi-core cable on hand, you can easily make a null modem yourself.
Figure 7.1 shows two null modem circuits using two DB25 connectors.
Rice. 7.1. Null modem schemes
There are two types of serial adapter port connectors, DB9 and DB25. These connectors differ in the number and purpose of pins. The DB9 connector has 9 pins and the DB25 connector has 25 pins. Despite the different number of conclusions, their functionality are the same.
If you assembled a null modem in accordance with the diagram above, and the serial adapter has only a 9-pin connector free, you can use a special adapter (see Fig. 7.2).
Rice. 7.2. Adapters DB25 - DB9
7.5. How to link computers through an asynchronous port
If you have two or more computers at your disposal, you can organize data exchange between them without using floppy disks and without installing network adapters.
To do this, connect the computers' asynchronous serial adapter ports using a null modem cable. After that, using special software, you can access from one computer, called the worker, the disks of another, called the server. At the same time, you can only work at a working computer, but you get full access to the disk subsystem of the server.
You can use Norton Commander or FastLynx as the software used to communicate between computers through the ports of the asynchronous serial adapter. Operating system MS-DOS version 6.0 includes its own means of organizing communication between computers via a null modem.
Below we'll look at using Norton Commander and MS-DOS version 6.0 tools.
Using Norton Commander
The most simple program that can be used to directly connect two computers via a null modem cable is Norton Commander. With this program, you can exchange files between computers, while you can only work on one computer.
Using a null modem and asynchronous adapters can be very useful if you need to copy a large amount of information from one computer to another. In this case, if the computers are not in local network, the process of copying via floppy disks can take several hours. Using a null modem, you can significantly speed up the copying process. Below we will give a brief instruction on how to link two computers through asynchronous serial adapters.
First turn off the power of both computers and connect them via asynchronous serial ports (COM - ports) with a null modem cable. Then turn on the computers and run Norton Commander on both computers.
For each computer, select linK from the Left or Right menu. At the same time, the Commander Link dialog box appears on the screen (see Fig. 7.3).
Rice. 7.3. Commander Link Dialog Box
Then you need to select the operating mode - "Master" (working computer) or "Slave" (server), and also determine the serial port that you will use for connection - COM1 or COM2. The null modem cable should be connected to this port.
For one of the connected computers, you must select the "Master" mode, and for the other - "Slave". In this case, you can only work on a computer that is in "Master" mode.
The Turbo Mode switch located on the Commander Link dialog box sets increased speed data exchange. Turbo Mode must be installed on both computers at the same time.
With Norton Commander, you can do the following:
- copy and move files from one computer to another;
- delete, create new files on the server, change file attributes;
- create, delete directories on the server.
With Norton Commander, you can't perform basic server disk operations such as browsing the directory tree and launching programs from the main computer.
If you are not satisfied with the capabilities of Norton Commander, use the MS-DOS version 6.0 operating system tools or connect your computers using a local area network.
Using MS-DOS tools
The MS-DOS version 6.0 operating system distribution includes software tools for organizing data exchange between computers through asynchronous adapter ports or through parallel ports. These include the Interlnk driver and the Intersvr program.
Using the Interlnk driver and the Intersvr program, you can get full access from a working computer to disks and printers connected to the server. At the same time, new devices appear on the working computer through which you can access disks and parallel ports of the server.
Thus, new disks appear on the working computer, as well as parallel ports. In terms of their properties, with the exception of speed, they are fully consistent with local drives and parallel ports on the computer. You can freely write and read files from these disks, run programs. If a printer is connected to the server, then you can print a document on it directly from a working computer.
Consider the process of combining computers through the ports of an asynchronous adapter.
To connect two computers, you need to connect them using a null modem. Then connect the Interlnk driver in the CONFIG.SYS file of the working computer:
DEVICE=C:DOSINTERLNK.EXEThe n parameter specifies the number of server disks you wish to use from the work computer. If you don't set this option, only three drives will be available:
DEVICE=C:DOSINTERLNK.EXEThen run the Intersvr program on the server:
INTERSVRNow logical drives server and its printer ports are available from your work computer.
Rice. 7.4. Server
In our case, three new disks with the names I:, J: and K: appeared on the working computer, as well as a new parallel (printer) port LPT2.
Through drives I: and J: you can access drives A: and B: located on the server, through drive K: to the hard drive C: of the server, and through the parallel port LPT2, you can access the device (printer) connected to parallel port LPT1 on the server.
Attention!!! Copying this article is prohibited!Introduction
Many people are faced with the problem of where to buy a cable to connect the receiver and a computer for software updates. We will tell you how you can solder a null modem cable to connect the receiver and computer through the RS-232 port. Cable tested on receivers: DRE 4000,5000,7300; Openbox FTA300,X800,X820, 770PVR.
Required parts for soldering
You will need two COM(mother) connector. The connector looks like this:
You will also need a housing for this connector:
These connectors are connected by a three-wire cable according to the scheme 5-5;2-3;3-2
You can use as a wire twisted pair, which is used to connect network cards.
The cable that will be obtained after soldering can be used to flash receivers and create card-sharing through a computer.
The author is not responsible if your receiver fails as a result of improper soldering. We remind you that this cable has been tested on these models: DRE 4000,5000,7300; Openbox FTA300,X800,X820, 770PVR. There are receivers, the cable scheme for which differs from the above!!!
A null modem cable is a very necessary thing in a satellite economy. First of all for firmware satellite receivers. But you can’t always buy it, so you have to do it yourself.
As I already said 0 modem cable we will come in handy first of all for flashing satellite receivers. And if for this you can use a short one, which is easier to buy, then for cardsharing through a computer you almost always need a long or very long one (I did it up to 15 m.). And it's better to solder yourself. And it is done quite easily.
How to do it yourself null modem cable (RS232) do-it-yourself tuner firmware cord?
We will need two DB-9F connectors, a soldering iron, solder, a cable - a twisted pair, as it suits me just right (you can also have another telephone at hand, it’s normal), circuits and skillful hands.
There are several connection options, but most often you need a cable with three pins. Well, if this one does not fit, then we make a complete one for all contacts in accordance with the figures below.
Not a full zero modem cable is almost always suitable. But he also has varieties when his contacts go
Contacts 2 - 2 and 3 - 3, 5 -5 direct
Contacts 2 - 3 and 3 - 2, 5 - 5 not direct
It is the latter that is not directly suitable most often.
The wiring of the rs-232 com port in satellite receivers can look like both “father” and “mother”.
“Mothers” are much more common, so I advise you to do with two “mothers” at the ends.
It is indirect null modem cable with two mothers, and with the calculation from right to left, suitable for flashing most satellite receivers, or for sharing.
Problems with the "firmware" of the receivers. No COM port. Laptop use
Most of the "old" computers and laptops, purchased more than 5 years ago, always had several COM ports (RS-232). At least there was always at least one "RS-232" connector.
Rice. 1. Connector on the computer case
Various external equipment was connected to it: mice, printers, modems, specialized equipment. Therefore, there were no problems connecting the receiver to the computer for “firmware”. It was enough just to connect, run the program to update the receiver software and calmly do everything you need.
In modern computers, the RS-232 connector is often missing. This is where problems arise, often very unpleasant ones. In most receivers there is no other way to "firmware" other than using "RS-232". And not all receivers have a “USB” input for connecting an external flash drive.
And sometimes there is another problem: the laptop has a "COM" port, but it works with receivers of one model, but not with others. This is due to the violation by the laptop manufacturer of the RS-232 data transfer standard. They do this in order to conserve battery power. If the manufacturer of the receiver was technically scrupulous and accurate, then a special chip for the "COM" port will be installed in the receiver. Thanks to this chip, the receiver will work with both a laptop and a computer. But installing a microcircuit increases the total cost of the product, and lately manufacturers have been saving even on these little things! Therefore, there is a problem of incompatibility between laptops and most receivers.
When using a computer, the problem of the lack of the necessary RS-232 ports is solved simply: you need to purchase additional module with "COM" ports. This board installed in the computer is called "PIC-COM" or simply "COM ports board".
Rice. 2. PCI board for computer with two "COM" ports
If you are not strong in computers and have never dealt with the installation of additional equipment in a computer, then contact a specialist! Otherwise, you can "kill" expensive equipment.
After installing the board in the computer, the operating system "Windows" - "OS" assigns a number to the newly installed ports, for example, "1", "2" ... "25".
When using a laptop, you cannot install a regular board from a computer: the standard and size are not the same. There are two ways to solve this problem: expensive, but high-quality, and cheap, but not fully compatible. In the first case, you need to purchase a special board with ports for the laptop. The price of these boards is high, and I was not able to purchase this board, even on order.
Rice. 3. Laptop board with "COM" port
And there is a catch: in the "old" and "new" laptops, there are two different standards for additional equipment! Before purchasing, check the instructions for your laptop!
If you could not purchase a board for a computer or laptop, then there is only one way out: “USB”. Practically in all modern models computers have a "USB" output, at least two, or even all eight! Various "USB - COM" converters are commercially available.
Rice. 4. Converter "USB - COM"
Rice. 5. Scheme of the converter "USB - COM"
How to solder a USB-COM adapter yourself. Option 1
How to make a USB-COM adapter yourself, which can be used to connect converters and other devices to computers that do not have an "iron" COM port.
Attention!
The adapter described below ensures that only the RX and TX signals are matched.
All other modem signals are disabled.
For most devices without hardware flow control, this is more than enough.
With Pilot VAF / MAF converters, the adapter works 100%
Go!
You will need the following parts for assembly:
1. PL2303HX (USB-USART bridge from Prolific) - 1 pc.
2. MAX232CSE (UART-RS232) - 1pc.
3. Quartz 12.00 MHz-1pc.
4. Capacitors 10 nF (smd1206) - 2 pcs.
5. Capacitors 1uF (smd1206) - 6pcs.
6. Resistors 27 Ohm (smd1206) - 2 pcs.
7. Resistors 1.5KΩ (smd1206) - 1 pc.
8. Mini-USB connector -1pc.
9. Connector DB-9 male - 1 pc.
10. Foil textolite for the board 48 * 22mm - 1 pc
Adapter diagram
Printed circuit board
Schematic and printable files in the format Eagle PCB Editor can be downloaded from this link
Assembly and setup
Here, in fact, everything is elementary - we make a board, drill 4 holes and solder all the details.
As a result, you should get such an adapter:
The board, so that it does not oxidize, can be blown out with polyurethane varnish or any quick-drying automotive varnish that is at hand.
Next, we connect this device to the port Computer USB.
Windows will detect a new device and ask for a driver
We go to the profile website and download the most latest version firewood
At the time of this writing, the most recent driver was this one.
After feeding the Windows driver, a new Prolific COM port should appear in the system: 
Now you need to check the performance of the adapter
To do this, on the adapter in the COM port connector, with a screwdriver or wire, we close pins 2 and 3 together (digits with pin numbers are usually stamped on the connector itself - take a closer look) Alternatively, you can solder a temporary jumper:
Next, run the program "Hyperterminal" (Start->Programs->Accessories->Communication->Hyperterminal)
There is no hyperterminal on Vista and Seven! Therefore, you will have to go to Google / Yandex to download the hyperterminal or any of its analogues.
We select our new COM port in the connection settings:
Now we start the connection, select English layout and try to print something.
The symbols of the pressed keys should appear on the screen:
If the letters do not appear, then check the installation
That's actually all!
Now it remains to remove the jumper from pins 2-3 and you can use the adapter for its intended purpose.
Those. the input of such a “converter” is connected to the free “USB” connector of the laptop, the driver (control program) is installed from the disk from the kit, and in system settings a virtual COM port appears with an assigned serial number.
How to solder a USB-COM adapter yourself. Option - 2
| Picture 1.General form |
 |
The proposed block in assembled form allows you to implement the principle: bought - connected. The device will allow users of personal computers to connect devices operating from the COM port (RS232C) to the USB port.
Estimated retail price: 540 rubles
The adapter will be useful in practical applications: for connecting various devices to a personal computer, as well as modems and programmers.
Specifications
Supply voltage from USB port: 5 V.
Consumption current: 20 mA.
RS232C connection speed: 110-230000 bps
Interface: USB1.1, USB2.0.
Supported operating systems: Win98, Win2000, WinXP, Vista, Linux, etc.
Overall dimensions of the device: 60x30 mm.
Contents of delivery
Adapter block assembly: 1.
Instruction: 1.
Design
Structurally, the adapter is made on a double-sided printed circuit board made of foil fiberglass, protected by a transparent heat shrink tube.
The adapter provides all modem signals: DSR, DTR, RTS, CTS, RI, DCD, as well as the main RXD and TXD signals.
Figure 2. Electrical circuit diagram
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Figure 3 View printed circuit board from the side of the details
Description of the block
principled circuit diagram shown on pic 2.
The central part of the device is a CP2102 microcontroller manufactured by SILICON LABORATORIES. The MAX3243 converter manufactured by Texas Instruments is used as a level driver chip. The adapter provides all modem signals: DSR, DTR, RTS, CTS, RI, DCD, as well as the main RXD and TXD signals.
Installing the device in the OSTo install drivers for your computer, you must first download the appropriate driver for your operating system.
Next, install the driver on your Personal Computer. Plug in the adapter. The operating system will detect it and "ask" for the driver, you should tell it the location of this driver (the place where it was unpacked).
After successful installation, the LED on the adapter should light up, signaling the readiness of the device for operation!
NEW Updated driver from 01/25/2011
1. Driver for Win Vista You can download
2. Driver for Windows 2000/XP/Server 2003/Vista (v5.0) You can download
3. Driver for Linux You can download
4. Driver for Win98SE You can download
5. Driver for OC Mac You can download
6. an144sw.zip- using this program, you can change the ID codes of the USB-COM adapter. This is necessary in order to be able to use several 8050s on one PC. Use only advanced users! You can download
BM8050 FUNCTIONAL TEST WITHOUT EXTERNAL HARDWARE
To check the transmission and reception of all necessary modem signals according to the connection of the COM device.
Install jumpers on pins 2-3, 4-6, 7-8 of the BM8050 COM connector.
Connect the device to the USB port of the PC.
See which port the OS has allocated for the device, for which go to Start --- Customization --- Panel Office --- System --- Equipment --- Dispatcher Devices --- Ports(COM and LPT) --- Silicon Labs CP210x USB to UART Bridge (COM1).
Run standard application HiperTerminal for Windows from Start --- Programs --- Standard --- Connection--- HiperTerminal.
Stop a running connection, if it is active, to do this, click Call --- Stop at the top.
See which port is used by the program to communicate with the device, for which go to the top left File --- Properties and opposite "Connect via" select the same port as in the Device Manager (in our case, COM1).
In the same window, make sure that "Hardware" flow control is selected in the program, for which click the button in the "Settings" center and select "Hardware" in the lower "Flow Control" window.
Exit the program settings by clicking OK, OK again.
Type the text "Text" in the HiperTerminal program, while the text "Text" is printed on the screen, which confirms that the device is working.
Remove the jumpers from pins 2-3, 4-6, 7-8 of the BM8050 COM connector.
Type the text "Text" in the HiperTerminal program, while there is no print on the screen, which confirms that the device is working.
Driver setup and port selection for USB-COM adapter
Here the first problems await us: firstly, the OS could assign too large a number to the virtual port, for example, "25". And the program for "firmware" of the receiver allows you to work with port numbers from one to four. Secondly, not all USB-COM converters can work with the firmware program and the receiver itself. The reason is that equipment manufacturers have manufactured their products and programs in different ways. It is necessary to check all converters individually for your program and your receiver. It often happens that the converter works with one equipment, but not with another.
If the first problem is solved by changing the port number in the OS settings, then the hardware, program, and converter compatibility problem cannot be solved.
To change the assigned OS number, you must change it manually. To do this, you need to enter the "Device Manager": "Start" - "Settings" - "Control Panel" - "System".
Rice. 15.6. "Control Panel"
In the window that appears, select the "Hardware" tab and click on the "Device Manager" button. The Device Manager window will open. In the window that appears, in the tree-like list, select the line “Ports (COM and LPT). In the drop-down list, you will see all the ports available on your computer. Select your virtual port: "USB to COM converter". I have a "Prolific" model converter.
Rice. 15.7. List of available ports
Click on this line with the RIGHT mouse button, in the window that opens, select the “Properties” option.
Rice. 15.8. Setting the selected port
In the window that appears, select the "Port Settings" tab. In the "Speed" line, select "115200", then click on the "Advanced" button.
Rice. 15.9. Configuring Port Settings
At the bottom of the window that opens, find the "COM Port Number" tab.
Rice. 16. Change the COM port number
Click on the tab and select the desired COM port number.
Note that some port numbers may be occupied by existing equipment, such as the built-in modem. You cannot use one port at the same time!
After completing the settings, click "OK" to save the changes made and completely exit the settings mode, closing everything previously open windows. After that, restart your computer to make the necessary changes. If you changed the “COM” number of the “USB - COM” port of the converter, then simply remove it from the computer connector and reconnect it.
Ready-made solutions for USB-COM adapters from manufacturers.
Adapter cable COM 9/25M -> USB AM 1m
Price - 300 rub.
Description Cable for connecting devices with a serial interface (RS-232) to the USB port.
Cable connectors or adapter COM25M, COM9M, USB A
Compatibility
USB 1.1/2.0 Compatibility
Support for Windows 2000, Windows XP
Other
Cable length 1 meter
Logistics
Package dimensions (measured in NYKS) 21.5 x 14.5 x 4.1 cm
Gross weight (measured in NYX) 0.136 kg
TRENDnet adapter cable 
Price - 500 rub.
Main
Manufacturer TRENDnet
Model TU-S9
Type of equipment Adapter cable
Diameter 28/24 AWG
Performance Options
Data transfer rate 500 Kbps
Powered by USB port
Power consumption 500 mA - maximum
Compatibility
System requirements RAM 64 MB
Support for Windows ME, Windows 2000, Windows XP
Other
RoHS Compliance
Cable length 0.6 meters
Weight 75 grams
Operating temperature 0 ~ 40°C
Package dimensions (measured in NYX) 23 x 16.8 x 4.6 cm
Gross weight (measured in NYX) 0.135 kg
External sources information
Link to the manufacturer's website www.trendnet.com
Adapter - USB-COM adapter (RS-232)
Price - 1500 rub.
The adapter is designed to use devices and adapters designed to be switched on via the Com (RS232) port, for example, this is very important when using modern computers that have only USB, in this case, using this adapter, you can use modern computers and laptops together with our devices and adapters, such as Scanner BMW, Scanner Mercedes, Scanmatik, etc.
Car service equipment, car diagnostics, diagnostic equipment, car diagnostics, car scanner, car scanner, diagnostic post, chip tuning, car diagnostic equipment Carbrain, UNISCAN, ADP-504, KKL-USB, KKL-COM, BMW scanner, Opel scanner, BMW 1.3 .6, Automan, Opel scanner, BMW scanner, engine tester, gas analyzer, engine diagnostics, dashboard diagnostics Transponder programmer, OBD-2, OBD2, odometer correction, U-581, engine start, crash data, crash date, crash date, speedometer, tachometer.
Although you may need to use a null modem cable (2-3, 3-2, 5-5) and an adapter like -
Add to the adapter USB extension cable here's a straight-through null modem cable.
- Retail value 100r.
- Type A-A
- Length: 1.5 m
But for the rest of the resources you need " flipped over" null modem cable.
- Retail price 155.00 RUB
- Connector type: DB9 F - DB9 F
- Length: 1.8 m
or this adapter:
STLab U-350 (RTL) Adapter COM 9M -> USB AM
Price - 350 rub.
Main
Manufacturer St-Lab
Model USB DONGLE SERIAL 1 PORT
Description The adapter allows you to connect a device with an RS-232 interface (for example, a modem) to a USB port on your computer.
Type of equipment Adapter cable
Cable connectors or adapter COM9M, USB A
Integrated USB connector Yes
Performance Options
Transfer rate 115200 bps
USB interface 1.1
Powered by USB port
Support for Windows 2000, Windows ME, Windows XP, Windows Vista, Windows 2003 Server
Package dimensions (measured in NYX) 17 x 13 x 3.2 cm
Gross weight (measured in NYX) 0.077 kg
External sources of information Link to the manufacturer's website