Prestige Portraits PRESTIGE 861 Leaflet

VDSL, the fastest offering of DSL, provides 

significantly higher bandwidth than other DSL 

technologies. VDSL technology, which is similar to 

that of ADSL, uses existing copper wires to deliver 

high-speed data services. 

The major issues with VDSL technology are the line 

codes to be employed, which can be divided into 

either single-carrier or multi-carrier modulation 

schemes. For example, QAM is the most widely 

used form of single carrier systems while DMT, the 

standard line code for ADSL, is the primary form of 

multi-carrier modulation. Both QAM- and DMT-

based systems can be designed for VDSL 

applications. However, DMT modulation 

dynamically adapts the bit rate to conditions on the 

local loop and offers excellent performance even 

over noisy lines. 

ZyXEL’s Prestige 861 series, which is a DMT-based 

VDSL modem, supports a complete range of speeds 

ranging from 64Kbps to 25Mbps. Symmetric speeds 

for the Prestige 861 series range up to 25Mbps at 

64Kbps increments while asymmetric speeds range 

up to 52Mbps downstream and 26Mbps upstream at 

64Kbps increments. The built-in 4-port switch 

allows multiple devices to share the bandwidth 

without the cost of additional network hardware.

DMT 3/4/5-band, 
ATM-based VDSL Modem/Gateway

The Prestige 861 series is a DMT (Discrete Multi-Tone)-based VDSL CPE. 

DMT modulation dynamically adapts the bit rate to conditions on the local 

loop and offers excellent performance even over noisy lines. Network 

administrators become free from manually testing lines and from constantly 

adjusting equipment to noise conditions. Both IEEE 802.3ah Ethernet in the 

First Mile (EFM) Task Force and IEEE T1E1.4 Working Group selected DMT 

as its worldwide VDSL line-coding standard. 

The high-bandwidth Prestige 861 series allows service providers to 

simultaneously deliver a variety of value-added services, such as broadband 

Internet access and multiple streaming video channels. With the Prestige 861 

series, small to medium business users can have much higher bandwidth for 

both symmetric and asymmetric applications while home users can enjoy 

interactive media-rich entertainment which was previously unavailable. 

With VDSL, traditional “copper wire” telecom operators may begin offering 

“triple play” multimedia services such as multiple high-quality digital video 

streams, high-speed internet access, and voice services in a way which 

provides a user experience similar to today’s other existing distribution 

systems (cable, terrestrial, satellite). New revenue can be generated with a 

minimal amount of installation time and expense.  

VDSL can be implemented quickly, even if there is only one phone line per 

tenant. The existing POTS or ISDN services may be kept while adding new 

broadband services.

The combination of a switch makes the Prestige 861 series more efficient 

and less expensive than a similar unit with an external switch or hub. The 

industry-standard HP Auto MDI/MDIX features enable automatic and 

transparent detection as well as automatic correction of cables. Product 

installation, debugging, and network maintenance become substantially 

easier and significantly more efficient. 

The VLAN feature in the Prestige 861 series offers the benefits of both 

security and performance. For example, various priorities can be assigned to 

differentiate real-time applications and Internet access applications via 

VLAN tagging. Such control enables service providers to turn on various 

broadband services to a larger number of customers more quickly and 

economically.