xDSL modem digital subscriber line technology is used for transmitting high-speed data on existing copper phone lines to homes and businesses in the Local Loop. xDSL modems are an attractive solution for service providers, enterprises and campuses to obtain high-bandwidth point-to-point service over existing infrastructure. The family of xDSL modems refers to modems that provide different types of DSL service.
Types of xDSL modems include those that provide asymmetric DSL (ADSL, ADSL2, ADSL2+), symmetric DSL (SDSL), high-bitrate DSL (HDSL), symmetric high-bitrate DSL (SHDSL, SHDSL.bis) and very high speed digital subscriber line (VDSL, VDSL2).
ADSL modems deliver up to 8 Mbps to the customer premises, allowing service providers to deliver high-speed data and video services. SHDSL modems provide symmetric service over distances up to 10 km.
The most advanced symmetric DSL modem technology, SHDSL.bis, uses TC-PM 16 or TC-PAM 32 line coding and multi-pair bonding technology to reach transmission rates up to 5.69 Mbps on 1 pair (2-wire), 11.4 Mbps over 4-wire, for a rate up to 22.8 Mbps over 8-wire. SHDSL.bis provides high-bandwidth transmission at a distance of up to 2.9 km (1.825 miles) on 26 AWG.
The new SHDSL.bis standard, utilizing multi-pair bonding, enables symmetrical transmission to distances up to 2.6 km at rates of up to 5.7 Mbps over 2 wires, 11.4 over 4 wires, and 22.8 Mbps. Extended ranges of up to 10 km are supported by SHDSL modems at lower rates.
VDSL modems are an attractive alternative to fiber to the home (FTTH), as operators are installing fiber up to the entrances of neighborhoods and using copper on the last leg.
VDSL modems operate at speeds up to 10 mbps with a maximum range of 2.5 km (1.2 miles) over 4-wire copper. The next-generation VDSL2 modems are to provide 100 Mbps according to the new ITU-T standards (ITU-T G.993.2).
No vendor of xDSL modems can match RAD’s wide selection of interfaces, flexibility and variety of product lines incorporating DSL technology.
