That information reached the user, the analog pulses pass through a demodulator, which are converted into the original digital signal. There are different types of modems that perform many functions. These devices are internal and external. Internal analog modem is placed in the computer case and connected directly to the motherboard. An external modem is a separate device that connects to a serial or parallel port and is powered from the mains.
Modems operate according to specific communication protocols, which are divided into several groups. Each group is responsible for certain settings. For example, the first accepts an analog signal and controls the encoding. Second - check coded signal for errors and if they exist it asks for retransmission, or gives an error report. In both cases, the device will shut down and report an error number or a request to reconnect.
For the organization of connection and exchange data between the RAM of the computer and the modem answers the third group of protocols – it specifies certain rules of the team. Knowing the encoding of the transmitted error to understand the cause of the outages. If you connect a new device, leave the default configuration or add configuration as described in the manual.
If when trying to connect, there are periodic errors, you can validate them using the standard commands. For example, the modem is not dialing, error: "No signal, check on the keyboard X3(X0). Keep in mind, the method will be useful only if the device is connected and is in working condition - you hear a long beep, but the dial tone is ignored.
You have seen the condition of a modem, but he passed out before sharing data that could occur due to a very quiet or very short signal the PBX. Try to type the command X2. Keep in mind, if the device does not have the desired sensitivity, a function will not help.
It so happens that the modem is disconnected while checking the user name and computer. View the value of the set timeout period configured for this connection - it is likely too short. To change the value, open "My computer", "Remote access", right-click the connection icon and select properties from the opened menu, find the "settings" button and choose the tab "Connection". Change the numeric value next to the line "cancel the call if not connected within" or uncheck this check box.
Cause of disconnections may be a bad line quality, interference, intermittent attenuation of the signal, the limited data transfer rate. Connection errors are eliminated by configuring the required settings, which are selected in accordance with the guide for the particular modem.