what is null modem serial cable

three types of connections: Male to female, male to male. Mother to mother. Each of the three connectors has crossover lines and straight lines, so there is a total of 6 connections in the same way.Question 2: How to identify the cross-serial line and direct-connect serial line?Check it with a multimeter. Suppose 2 and 2 pass. The general 3 and 3 are straight

What does the ADSL modem mean? often have netizens to consult this problem, ADSL modem is a modem, commonly known as "cat", users of ADSL broadband after (telephone line internet), must use ADSL modem this equipment, can normal in

1, LCD TV cable Signal line interface (analog signal) is a radio frequency interface (also known as RF interface, coaxial cable interface, closed route interface), digital signal through the set-top box to convert analog signal video output to the TV, in order to watch TV programs.2, TV or HD set-top box on the HDMI interface

Line sorting is generally divided into two kinds of standards, one is the 568A standard, the other is the 568B standard, and generally we use the network cable is the most commonly used 568B standard, its network cable connector s

This problem has actually plagued me for a long time. I have asked many people what is "null? What's the purpose? Most people answer: "null is a special 0 defined by the system. Pointing your initialized pointer to it can prevent the evil effects of" wild pointer. " Toda

What is the function of not NULL in the new field when the statement ' AAA ' varchar (one) is not null? What is the function of not NULL in

after the hair can be a. So hurry up and tundish. Serial hard disk is so people pay attention to. Below we share the next serial hard disk and the same port hard drive data cable difference, the following figure: Serial port and parallel port hard drive data

What is the value of the null and non-null settings when MySQL creates a table? Reply to discussion (solution) Did anyone answer???? I generally try not to use nullIf your 0 and null or ' and null have different meanings, t

This is a two function!Srand functionOne is the Srand function! This is used before calling the rand () function! Rand () is a function that produces a random number! And Srand is a function that sets the seed of a random number! Usually these two functions are used together

");------------ When the value is =null, a null pointer exception is thrown and the S1.equals ("Sky") is changed to "Sky". Equals (S1) to avoid throwing exceptions6. Empty string and Null difference　　TypeNull represents the value

check the phone serial number IMEISometimes the brush, or mobile phone repair or other operations, may use the phone serial number IMEI, the following several ways to view the phone string number.Method 1 1For mobile keyboard, enter "* #06 #" in the phone keypad, in the smart machine without the keyboard, please enter the address Book, and then enter "* #06 #" on the dial pad.END Method 2: Vi

Non-static properties are used when NULL parameter constructs automatically generate objectsCode: PackageCom.swift;//automatic generation of objects using the parameterless construction method, the serial number is continuously self-increasing Public classPerson {Private intCount//If you are using a non-static property when defining a class, the result

The C + + language definition says that each pointer type has a special value----"NULL pointer".A null pointer is conceptually different from an uninitialized pointer. A null pointer ensures that no object or function is pointed to, and the uninitialized pointer may point to

What is the difference between echo and/dev/null in command for clearing file content? We know that there are many methods to clear the file content. This article only talks about the differences between echo "And/dev/null. 1. What is