BRI Functional groups: TE1, NT2, etc.

datchcha

I am having some issues remembering, and visualizing the model of the ISDN map. Devices like TE1, NT2, NT1, LT, and ET really do nothing for me, and my resources, which are the (2) Cisco books, and Sybex only give the device labels that I mentioned earlier.

Can you offer assistance, and give an example to what these titles correspond to? For Example, is a DSL modem or Modem a TA device, and a networking card in the system a TE2 device? Example: would a DSU/CSU be a NT2 device, “devices that have some intelligence to perform switching and concentrating to direct traffic”?

Thank you

dtlokee

TE1 is a device with the ability to ommunicate using ISDN protocols directly, such as an ISDN Phone, a router with a ISDN interface (such as a 2600 with a WIC-1BU card).

TE2 is a device whish cannot directly communicate with the ISDN network and requires a TA to complete the connection. This could be a PC using a serial interface, or a router using a serial interface, or a regular analog phone.

ISDN network

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NT1

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TA

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Serial Interface of router

NT1 is the device that terminates the ISDN BRI connection

mikej412

A picture is worth a 1000 words.... Figure 12-1.
Integrated Services Digital Network Overview - ISDN Devices

You might as well learn the "Reference Points" while you're there.

datchcha

Thanks.