Details on ISDN network terminals in Network Access Technology

Let's talk about the ISDN network terminal in network access technology. Before giving you a detailed introduction to the ISDN network terminal, first let everyone know the corresponding parameters in the ISDN network terminal, and then give a comprehensive introduction to Internet sharing, select the simplest solution of using a Broadband Router.

ISDNIntegratedServicesDigitalNetwork) integrates business Digital Networks

It is developed by telephone integrated digital network IDN. The ISDN network terminal is a combination of digital exchange and digital transmission. It provides existing services in various communication networks in a fast, accurate, economic, and effective manner, and integrates communication and data processing, it has created many new businesses unprecedented.

The ISDN network terminal is a fully digital network. In other words, no matter whether the original signal is a voice, text, data or image, as long as it can be converted into a digital signal, it can be transmitted in the ISDN network. In the traditional telephone network, the network is digitalized, but analog transmission is still used between users and telephone bureaus, which is prone to distortion due to the accumulation of Noise along the way. For ISDN network terminals, user line digitalization is realized, end-to-end digital connections are provided, and the transmission quality is greatly improved.

As the ISDN network terminal implements end-to-end digital connection, it can support various services including voice, data, and image. As electronic communication continues to expand globally, many of us need to exchange information with users in different regions. Nowadays, communication requires not only simple sound exchange, but also sharing different information in various formats.

For example, some people need high-speed data and file transmission, some may need multimedia and conference television, and some may want to access the central database. The services of the ISDN network terminal cover all the services of the existing communication network, such as fax, telephone, visual text, monitoring, email, visual phone, conference and television.

It can meet the needs of different users. Another basic feature of the ISDN network terminal is to provide users with standard inbound interfaces. You can combine terminals of different business types, connect to the same interface, and change the terminal type at any time.

There are two main types of ISDN network terminals: basic rate BRI) and basic group rate PRI ). All interfaces provided by the Telecommunications Board to common users are BRI interfaces. The original twisted pair wires can be used at a rate of 144Kb/s. BRIISDN can provide two B-channel 64 K) and one D-Channel 16 K on a pair of twisted pair wires. Channel D is used to transmit signaling, and channel B is used to transmit voice and data.

One phone only occupies one channel B. Therefore, multiple services or conversations are performed simultaneously. The PRI interface speed is 2.048 Mb/s, which is used for applications that need to transmit a large amount of data, such as PBX and LAN interconnection. Devices of the ISDN network terminal are divided into three types: network terminal NT1, terminal adapter TA, and IISDN network HbA card.

ISDN network terminal (NT1 or NT1PLUS), which is the terminal device of the user transmission line. It is a key device that transfers and receives digital signals over a common telephone line. This device is installed in the user, is the essential hardware to realize the function of N-ISDN network terminal. Network terminals are divided into two types: basic rate network terminal NT1) and one group rate network terminal NT2. According to ITU, an ISDN User line should be able to connect eight terminal devices at the same time, while NT1 generally only provides two S/T interfaces. When you need to access more terminal devices, you can use an extended connection port. The connection method is shown in:

NT1 provides the physical layer conversion function between the U interface and the S/T interface, enabling ISDN network end users to directly access standard ISDN devices through interfaces provided by NT1 on existing telephone lines. NT1 provides users with 2B + D bidirectional transmission capabilities. It supports up to eight terminal devices in point-to-point mode, and allows multiple ISDN User Terminal devices to use one D channel. NT1PLUS is an enhanced type of ISDN network terminal. The biggest difference between NT1PLUS and NT1 is that NT1PLUS can be directly connected to a common analog telephone, while NT1 must be connected to a digital telephone. NT2 provides a four-line bidirectional transmission capability of 30B + D and regularly performs network maintenance. It is often used in ISDN small switches. At present, some manufacturers have provided the NT2 function for user terminal devices, commonly known as the u Interface.

ISDN network terminal adapter TA (TerminalAdapter), ISDN network terminal adapter TA can be used to convert the line of the ISDN network terminal into two common analog lines, there is an ISDN interface on the TA, there are three other user interfaces, two of which are the interfaces of the common analog phone on the 11th and one is the RS232D data interface. During use, the ISDN line is inserted into the ISDN interface. Two common telephones can be connected on the two analog telephone interfaces of listen 11. The RS232D interface is connected to the serial or parallel port of the computer through a cable. In this way, you can call the internet. TA can automatically select an idle B channel for communication.

For example, when you only use channel B to access the Internet, if an external phone calls in, the phone will ring and you can normally answer the phone. If you need to make an external phone call at this time, as long as you mention the phone, TA will automatically select the free B channel for the call.

Of course, if you use two B channels at the same time, you will hear a busy voice when calling your number. There are usually some indicators on the TA to indicate the use of the current B channel. TA connects traditional data interfaces such as V.24 to the ISDN line, so that non-standard ISDN network terminals that cannot directly access the ISDN network terminal and the external devices connected to the ISDN. It supports accessing the Internet from a single PC, and can connect to multiple devices, such as analog telephones, G3 fax machines, and modem devices for communication.

ISDN card ISDNPC card), which is installed in the expansion slot of the computer and connects the computer to NT1 or NT1Plus, however, the connection to the ISDN card must be connected to the TA RS232 data interface through the computer serial port or parallel port, rather than directly connected to the NT1. The connection method is as follows: