What is the loop test?

Loopback test is a simple method to find out whether communication circuits work at a basic level. This often includes a loop connection to the circuit and verify that the transmitted data will be returned to the sender. Loopback testing is commonly performed on serial, network and telephone connections. Technicians use this method for rapid testing to see if data ports, cables and connection work. For example, a loop device can be connected directly to the computer's serial port. If the data is sent and then successfully received on the same port, it is likely to work correctly. The loop device can then be moved to the end of the cable connected to the port and the data can be sent again. If it goes through, the cable is likely to work properly and the device can be moved further along the link for further testing. On the data receiving line. The simplest form of recommended standard (RS) 232 serial loop test can be performed in this way using a standard serial connector. A more thorough test can be performed atBy putting several hardware handsharing signals in connection. For example, the Clear to SEND (CTS) line can be connected to the shipping application line (RTS). The line of the Ready data terminal (DTR) should also be connected to the Ready (DSR) data line.

RS 422 Serial connection was used on Apple® computers before the universal serial bus (USB). RS 422 and RS 485 use a pair of differential transmission data signals and another pair for receiving data. In this way, hardware hardware hardware hardware is paired. Each of these pairs must be connected to the corresponding pairs for the loop test. For example, a number of positive transmission data are connected to a positive ATA and negative to negative reception.

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Ethernet loop test can be performed with a similar data line connection. The positive transmission data line is connected to a positive data receiving line. Negative dataThe lines are directed in the same way. These connections are often connected to a customized registered Jack 45 (RJ45) jack or port. Other network standards such as Bell Labs T-No-Carrier 1 (T1) and Gigabit Ethernet can be tested with similar cabling.

There are also more complicated network loops, which are more like the launched protocol analyzers. In addition to the basic loop test, this type of analyzer also checks signal quality, data loss and similar properties. Many information technology staff (IT) use these devices to monitor their networks everyday.