A guide to
the DAH
Data Over Cable Service Interface Specification
is an international telecommunications standard that permits the addition of
high-bandwidth data transfer to an existing coaxial based TV distribution system.
Why choose cable broadband access?
DOCSIS is employed by many cable television operators worldwide to provide Internet
access. There are an estimated 100 million homes connected by DOCSIS worldwide, making
it a reliable and established system to deliver gigabit speeds without the installation of new
Cable internet access, enabled by DOCSIS, will not affect the delivery of the TV
channels. The data signals are carried in the same cable using different frequencies as a
part of the spectrum is reserved for bidirectional IP traffic (upstream and downstream/
to and from the internet).
The use of the coaxial cable for broadband access ensures that there are high streaming
bitrates and error free transmission necessary for video and on IPTV service without
the need for data cabling.
The Teleste DOCSIS Access Hub (DAH)
The DAH is an access network hub for extending IP network
inside hospitality properties by utilising existing coaxial
cabling. It is a dynamic and economical method which will
bring high-speed internet to every room and upgrade the
network capacity for IPTV, and other on demand online
video services.
To provide internet access in individual hotel rooms or
cabins a cable modem is connected to the existing
coaxial cable.
A guide DOCSIS & the DAH
Teleste DAH
Coax Cabling or Data Cabling?
Using a coax cable
Already in almost
every building that
has TV screens
installed. It is also
very easy to add on
extensions to the
existing network.
Can carry all forms
of live TV, radio,
CCTV as well as
having space for
high speed Internet
Cost of installation
The cabling is
already in the
building & only some
simple maintainance
is required to make
a TV and data
Best used for
Upgrading existing
properties as a coax
network is already
installed to each TV
Data cabling can
only be used to
carry data, with a
100m limitation on
Cost of installation
It is costly and
disruptive to install
a new Cat5 network
into an existing
building, as it is
invasive to the fabric
of the building.
Best used for
New build
properties where it is
easy to run a Cat5
cable network to
every TV point
during the build.
Using a data cable
Data cabling can be
found in most
buildings, but this
rarely reaches every
Using coax network for broadband access
In order to introduce cable broadband into your network, you will need to install the
Teleste DOCSIS Access Hub (DAH) to the existing coax network. The DAH enables the
use of upstream and downstream channels of the network for transmitting high-speed
data as RF signals. These signals are sent in parallel with the traditional TV through the
same cabling. The DAH receives the gigabit Ethernet pipe from the internet service
provider, it then plugs directly into the Internet gateway/router or data switch, via a
normal Ethernet patch cord.
The RF signals will need to pass through an amplifier that is capable of boosting the
whole signal range that the coax is using. An amplifier has been built-in to the
DOCSIS Access Hub – this means that no extra devices are needed to deliver traditional
broadcast TV.
Broadband cable Internet access requires a cable modem at every end point to turn the RF signals back into regular Ethernet traffic; this can then be used
by normal IP devices with RJ45 connectors on them. The modem can be a data
outlet or can have a combination of data and WiFi within the same small box.
Cable Modem
A guide DOCSIS & the DAH
Samsung HE694 Series Hospitality TV
The Samsung HE694 series hospitality television now has a cable modem built in. The TV
used with the DAH can provide Ethernet data, WiFi, and IPTV direct from the TV screen
itself. This hospitality solution only requires a power cable and the existing aerial cable at
each TV point.
Equipped with the capabilities of Teleste DOCSIS Access Hub (DAH) and DOCSIS HTV, Samsung’s HE694 television enables hospitality businesses dependent on coax network to
easily convert traditional TVs into full IP interactive infotainment solutions.
A guide DOCSIS & the DAH
Using & Maintaining the Coax Network
On the rare occasion that the coax cable needs repairing the reliability and speeds of
the network are affected - these usually just require simple fixes. The most common
problems are usually due to loose connectors which need tightening or badly
corroded wall outlets that need replacing. These problems affect the signal levels and
add unwanted noise to the network. Noise on a DOCSIS network is similar to an
unwanted hum on an audio system - it interferes with the signals, and negatively
affects the performance. The noise can prevent the DAH from hearing the signals
coming back up the coax cable from the modems, this stops the two way
communication that ethernet devices need.
The trouble spots that are usually found:
• Unterminated ports on amplifiers
• Open ports on splitters
• Loose connectors
• Badly made cable splices
• An unskilled repair has been made to a break in the system
F terminator connector
Basic leakage detection is simply injecting a tone into the network at the headend and
then walking around the building (with a scanner), looking for the tone that is leaking
out of the network. If a signal can escape the shielded network, then at the same time
significant noise can get in.
In order to ensure that the installation and ongoing maintenance is simpler the DAH
has a built in spectrum analyser to show noise on the return path signal. The spectrum
analyser is a visual graph that shows the amount and level of all the noise that the DAH
is receiving.
A guide DOCSIS & the DAH
DOCSIS Guide_06/16 Copyright © 2016 Teleste Corporation. All rights reserved. TELESTE is a registered trademark of Teleste Corporation.
Removing Noise (basic leakage detection)