Comprehensive Analysis of complete ISDN Terminal Guide and technical introduction

A comprehensive analysis of the complete guide and technical introduction of the ISDN terminal. When using the ISDN terminal, the virtual lan isdn terminal is often set up, in the following article, I will reply to you one by one, so that you can get what you want.

Technical Introduction

ISDNIntegrated Service DigitalNetwork ". In addition to phone calls, it also provides services such as videophone, data communication, conference and television, in this way, the telephone, fax, Data, images, and other services are integrated in a unified digital network for transmission and processing. This is the name of "integrated business digital network.

There are two types of ISDN: narrowband and broadband. Narrowband ISDN has two interfaces: basic speed 2B + D, 144 kbps) and one group speed 30B + D, 2 Mbps. The basic rate interface includes two independent B-channel 64 kbps) and one D-Channel 16 kbps. Channel B is generally used to transmit voice, data, and images, D is used to transmit signaling or group information.

Broadband can provide users with communication capabilities at or above 155Mbps. However, due to the complicated technology and huge investment of the Digital Network for broadband integrated services, it is not likely to be put into use in large quantities. However, the Digital Network for narrowband integrated services is very mature and fully qualified for commercial promotion, as a result, the overall service digital network of ISDN activated in various regions is actually narrowband ISDN.

The bits used for digital line data transmission are at least 10 times better than telephone lines. ISDN is widely used, but for ordinary people, only Internet access is the most commonly used. As the activation scope of ISDN is much wider than that of ADSL and LAN access, ISDN seems to be the only option for users who do not have broadband access, after all, kbps is faster than dialing;

ISDN charges fees based on the same time as the phone number, so some users with less time to access the Internet, such as users with less than 20 hours a month, are much cheaper than using ADSL. In addition, because the ISDN line is a digital line, it is much better to use it to make phone calls, including network phones.

Advantage Analysis:

◆ Integrated communication business: using a user line, you can call and send and receive faxes while surfing the Internet, just like two telephone lines.

◆ High transmission quality: the end-to-end digital transmission improves the transmission quality significantly.

◆ Flexible and convenient to use: you only need one inbound interface and a uniform number to get the services you need from the network. You can connect to multiple different types of terminals on this interface, and multiple terminals can communicate at the same time.

◆ The Internet access speed can reach 128 kbps.

Disadvantage analysis:

◆ The speed is not fast enough compared with access methods such as ADSL and LAN.

◆ Online fees will be high for a long time.

◆ Device fees are not cheap.

Required hardware:

Figure 1 ~ Figure 3 shows three common device connection methods. Different hardware is required based on different connection methods. The concept of standard ISDN terminal and non-standard ISDN terminal will be involved here. For example, digital telephones and four types of fax machines, that is, G4 fax machines, the transmission rate and quality are greatly improved compared with ordinary fax machines, an A4 file can be transmitted in 3 seconds. All files belong to the standard ISDN terminal and can be directly connected to the ISDN line for use.

The computer, telephone, and fax machines that we are familiar with are all non-standard ISDN terminals) connect to NT1 before connecting to the ISDN line. NT1 + integrates the functions of the adapter and NT1, so that non-standard ISDN terminals can easily connect to ISDN. Common ISDN devices include:

◆ Isdn pci plug-in card: It is similar to the NIC and is mostly a PCI interface. After it is installed on a computer, it can be connected to the Telecommunications Bureau by providing NT1. The price is generally 200 ~ 300 yuan. With a simulated interface, you can connect to a phone.

◆ Isdn ta: it is an external product, mostly USB interface. It supports hot swapping without external power supply. The shape is generally relatively small and chic, easy to carry, and is an ideal choice for mobile office, small office and home. The price is generally between 500 and ~ About 600 yuan.

◆ NT1: A smart network terminal. Generally, it provides two terminal interfaces to connect to a digital phone.

◆ NT1 +: an extension of NT1. Unlike NT1, NT1 can directly connect analog devices, such as analog phones, three types of fax machines, and modem devices. The Telecommunications Board generally provides this device.