VC-400RT
+
Managed VDSL2 CPE Router MANUAL Ver. A5
107
3. Symptom:
VDSL Link cannot be established.
Cause:
VDSL setting failure or phone cable length is over the specification limit.
Solution:
3.1 Please make sure that the phone wire must be connected between VC-400LT(CO)
and VC-400RT+ (CPE) when both are power on. VC-400LT (CO) will do link speed
function depending on phone wire length, therefore if VC-400LT (CO) can’t detect
VC-400RT+ (CPE) over phone wire while both power on, this will cause the link to fail.
3.2 Please check phone wire, we recommend use 24-26 gauge with twisted pair and
without rust.
3.3
Please reinsert power when change cable length or link time over 3 minutes.
Note:
Phone wire must meet CAT 3 standard or above and
without clustering
, otherwise will
cause more cross talk issue to reduce DSL power driver.
4. Question:
What is VDSL2? (Only reference)
Answer:
Very-high-speed digital subscriber line 2 (VDSL2) is an access technology that exploits the
existing infrastructure of copper wires that were originally deployed for traditional telephone
service. It can be deployed from central offices, from fiber-optic connected cabinets located
near the customer premises, or within buildings. It was defined in standard ITU-T G.993.2
finalized in 2005. VDSL2 was the newest and most advanced standard of digital subscriber
line (DSL) broadband wireline communications. Designed to support the wide deployment of
triple play services such as voice, video, data, high definition television (HDTV) and
interactive gaming, VDSL2 was intended to enable operators and carriers to gradually,
flexibly, and cost-efficiently upgrade existing xDSL infrastructure. The protocol was
standardized in the International Telecommunication Union telecommunications sector
(ITU-T) as Recommendation G.993.2. It was announced as finalized on 27 May 2005,[1] and
first published on 17 February 2006. Several corrections and amendments were published in
2007 through 2011.
VDSL2 is an enhancement to very-high-bitrate digital subscriber line (VDSL),
Recommendation G.993.1. It permits the transmission of asymmetric and symmetric
aggregate data rates up to 200 Mbit/s downstream and upstream on twisted pairs using a
bandwidth up to 30 MHz. VDSL2 deteriorates quickly from a theoretical maximum of 250
Mbit/s at source to 100 Mbit/s at 0.5 km (1,600 ft) and 50 Mbit/s at 1 km (3,300 ft), but
degrades at a much slower rate from there, and still outperforms VDSL. Starting from 1.6 km
(1 mi) its performance is equal to ADSL2+. ADSL-like long reach performance is one of the
key advantages of VDSL2. LR-VDSL2 enabled systems are capable of supporting speeds of
around 1–4 Mbit/s (downstream) over distances of 4–5 km (2.5–3 miles), gradually
increasing the bit rate up to symmetric 100 Mbit/s as loop-length shortens. This means that
VDSL2-based systems, unlike VDSL1 systems, are not limited to short local loops or
MTU/MDUs only, but can also be used for medium range applications.