422 null modem

The second converter requires a null modem connection between it and the device, since our converter is configured as DCE on the RS side, and the device cabling is also DCE. See the connection diagram for CASE 1. In this case, the first RS Converter connects to the Computer with a Standard serial cable wired pin 1 to 1, 2 to 2, etc. The original Null Modem Cable is set aside, not used. A new Standard serial Cable is connected to the device and the second converter.

See the connection diagram for CASE 2. A3: CASE 3: In the third case, we want to extend a set of RS connections between two devices, but we don't know how either port is configured. Both devices use DB9F female connectors. We have a voltmeter. We know the converters are DCE devices. So, we connect a Standard cable to the device, power it up, measure between Pin 5 of the cable to Pin 3. This connection should be okay.

If almost no voltage on Pin 3, check Pin 2. If it has the minus voltage, use a Null Modem Connection between the device and converter to swap the pin connections. Make a similar test for the RS connections at the other end. The voltage should be on the cable pin connecting to Pin 3. The pin numbers for the RS connections are not shown, they may vary according to the model, but the signal name will be shown on the data sheet.

Note: These connection figures do not show power supplies or handshaking lines needed to power "port powered" converters. Western Sahara Yemen Zambia Zimbabwe. Learning Center. Please note our new company name.

How do I Connect them? This information should help you make the connections needed for the most common connections. Download White Paper. Newsletter Signup phone: email: info advantech-bb. Cellular Routers. AirborneM2M WiFi Wzzard Wireless Sensing Platform. Wireless Accessories. Industrial PCs. Standmount Embedded Automation Controllers. Fiber NIC Cards. Unmanaged Media Converters. Managed Media Converters. FTTX Products. Mode Converters.

Modular Chassis Series. Power Over Ethernet Products. Telco Products. Posted: April 04, Categories: Serial , null modem. Tags: serial , rs , db9 , db25 , db Author: Nicholas Watkins. A standard DB9 AT cable pinout non-null modem Originally, all serial cables were AT cables and could not connect two devices such as two computers directly. A standard pinout featuring the two most common null modem cables, DB9 and DB25 Null modem cables are still somewhat common today, having been used on many machines for a few decades.

My Shopping List. Last Added Items. Add to Cart Add to Cart. Remove This Item. Go to Shopping List. Recent Posts. Simplifying the Many Differences among Ethernet Cables. Why Custom? Time to Get Organized with Cable Management. November October September May If the transmitter is ready to send data, then it sets the signal on the RTS line. If the receiver is ready to receive data, it sets the signal on the CTS line.

If one of the signals is not set, no data transfer will occur. If the data cannot be received, the receiver transmits the Xoff symbol. To resume data transmission, the Xon symbol is sent. How can I check the operation of RS? Then all the transferred data will be accepted back. If you have a full RS, then you need to unzip a special stub.

Allows you to simultaneously send and receive messages on separate lines full duplex , but uses a differential signal for this, i. The potential difference between conductors A and B. The data transfer speed in RS depends on the distance and can vary from 10 kbps meters to 10 Mbps 10 meters. In the RS network, there can only be one transmitting device and up to 10 receiving devices. The RS line is 4 wires for data transmission 2 twisted wires for transmission and 2 twisted wires for receiving and one common GND ground wire.

Twisting wires twisted pair with each other allows you to get rid of interference and interference, because the interference acts equally on both wires, and the information is extracted from the potential difference between the conductors A and B of one line.

Logical 1 corresponds to the difference between A and B less than The RS standard does not define a specific type of connector, usually it can be a terminal block or a DB9 connector. RS pinout depends on the manufacturer of the device and is specified in the documentation for it. Because the distance between the receiver and the transmitter RS can reach meters, then to prevent reflection of the signal from the end of the line, a special ohm termination resistor or "terminator" is put.

Then you can use the software to work with the COM port.