ISDN Concepts

Hello

Could someone please explain the difference between an NT2 device and Local Termination Equipment.

I'll explain why I ask:

R Reference Point is the point between TE2 device and TA.

S Reference Point is the point between Router and NT2.

T Reference Point is the point between NT1 and NT2.

U Reference Point is point between NT1 and Local Termination Equipment in a carrier network.

Thanks in advance

NT2 (Network termination type 2) is the device used to direct traffic from ISDN devices (TEs) to an NT1. It provides switching and concentrating and can sometimes even be a private branch exchange (PBX).

NT1 (Network termination type 1) is the device used to convert a 4-wire ISDN connection to the 2-wire ISDN used by the local loop facility.

Local termination (LT) This is the same device as an NT1, but located at the provider’s site.

References points:

TE1----S----NT2----T----NT1----U----ISDN Switch
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TE2----R----TA----|