2 Digital subscriber line VDSL2
2.2 Layout of VDSL2 connection

As it is already mentioned, xDSL connections allow more efficient utilization of existing local loops (based on metallic symmetrical pair) for the provision of new services than those for which it was the lines originally designed. Therefore, it must be assumed that the service POTS or ISDN-BRA is already on the lines operated together with a VDSL2 connection and it must not in any way affect this coexisting service (this applies, of course, vice versa). For this reason, VDSL2 connection operates in the modulated frequency band and both services on the subscriber line is additionally separated by frequency filters called as Splitters. Telephone and data signals can be transmitted in both directions over the same line in the same time.

The basic diagram of the VDSL2 connection is similar to the older ADSL connection.

High-speed transmission of digital signals at VDSL2 connection provide the modems VTU-R (VDSL2 Termination Unit - Remote) on the subscriber side and VTU-C (VDSL2 Termination Unit - Central) on the provider side. The modem at the side of your provider is usually part of the local multiplexer called as DSLAM (DSL Access Multiplexer), which centralizes the digital streams from all connections in the specified locality.

The basic diagram includes the following functional blocks and interfaces:

- DSLAM - DSL subscriber multiplexer,
- Splitter - frequency filter on the subscriber and provider side - in the case of service options without the concurrence of active service POTS or ISDN-BRA is the splitter optional
- VTU-C – VDSL2 transceiver (modem) on the provider side,
- VTU-R – VDSL2 transceiver (modem) on the subscriber side,
- U-RV - physical interface terminating lines on the subscriber side,
- U-CV - physical interface terminating lines on the provider side (located in exchange),
- U-RV2 - physical interface between the splitter and the modem on the subscriber side,
- U-CV2 - physical interface between the splitter and the modem on the provider side,
- T/S - physical interface between the VTU-R, followed by the network infrastructure on the subscriber side (LAN (Local Area Network)),
- Z/U0 - physical interface twisted pair running POTS or ISDN BRA with limited frequency band by HUB.