Provide digital physical channel and switch digital trunk interface on the public telephone network, so that users can exchange voice and other information with users on the public telephone network
Digital trunk refers to providing a digital physical channel and switch digital trunk interface on the public telephone network, so that users can exchange voice and other information with users on the public telephone network.It also refers to a data transmission network that uses digital channels to transmit data signals.Its main function is to provide users with permanent and semi permanent digital data transmission channels, which can be used not only for communication between computers, but also for transmission of digital fax, digital voice, digital image signals or other digital signals.
FirstOperatorThe voice service provided is 2.048Mb/s.After access to the ISDN network, you can directly use the telephone to communicate with the outside.
Second, the voice line from the router to the PBX device can be connected to Fax and a telephone under the PBX device.The phone can contact the intranet IP Phone through the router.
Note: Usually used for voice service, one PRI service can take 30 voice lines.
PRI isISDNPrimary group access provides a 30B+D path for users to connect to small switching equipment.In principle, it does not belong to relay (relay generally refers to two telecommunications intermediaries).
B refers to channel B: used for data and voice
D refers to D channel, used for signal and control
DIDDirect Dialing meansPBXThe small switch can dial in directly. It can be PRI, ordinary subscriber line or trunk line between the office and the small switch[1].
Advantages and disadvantages
Announce
edit
advantage
Digital relay is a relay form following the emergence of analog relay. Based on ISDN technology, digital relay has better support for number transmission, accurate billing and other services.
shortcoming
One digital trunk is 30 channels, which is good in concentration. However, the problem is that if the PRI is broken, the 30 channels will be completely broken, and the redundant error tolerance capability is lacking
The price is expensive, mainly due to the high monthly rent.
Remedies
Intelligent IP trunking can be used to achieve outgoing line redundancy.If the number one communication service is opened, full redundancy can be achieved.[2]
