4
1 What Is A Telephone Hybrid?
DHY-04HD Single Automatic HD Voice Hybrid, AES/
EBU & Analogue I/O With Ethernet
The DHY-04HD version can be used on a 3G or GSM cellular (mobile) phone
network instead of a telephone (POTS) line. The DHY-04HD can accept a
SIM card in the rear panel slot and by connecting a suitable GSM antenna,
the DHY-04HD can receive and make high quality broadcast calls over the
cellular network, converting the 3G or GSM call to the 4 wire audio signal to
and from a connected mixing console. The module used in the DHY-04HD is
quad-band GSM and 5 band UMTS/HSPA+, so it can take and make calls on
any 2G GSM, or 3G network.
Ideal for studios in remote locations, for OB vans and trucks on the
move, and in emergency situations where a telephone landline can’t be
guaranteed, the DHY-04HD offers outstanding performance.
The DHY-04HD has all features of the DHY-04 together with some additional
front panel indicators. There are two LEDs, one for SIM enabled and one for
GSM Network availability. Additionally there is a push button which allows
the mobile signal level to be displayed on the meter LEDs.
Product Function:
Provides separation between send and receive signals on a 2G or 3G
network, provides professional level balanced input & output signals and
has echo cancellation.
Typical Applications:
Radio & TV station outside broadcast vehicles for talk shows, telephony
interface to the mixer.
Backup hybrid to cover failure of main landline.
Main studio Hybrid for installations where the landline is unavailable or
unreliable
HD Voice:
HD Voice uses a coding system (also known as WB-AMR) for audio data that
provides a significant enhancement on the quality of cellular phone calls.
The use of HD Voice is dependent on 3 criteria -firstly the method has to be
supported by the network (and this may be limited by the users contract)
and when different networks are involved in the call the interoperability
between the networks. Secondly the actual equipment used by both ends
of the call must be HD Voice compatible. Both these requirements will be
established on call connection, which leads to the third criteria which is the
signal quality, and this can vary during the call. Normally the Hybrid will be
used in a fixed location install – even OB trucks are normally stationery - so
the position of the antenna can be refined for best signal quality, however
the far end maybe from a cellular phone so may vary in quality which can
lead to the familiar dynamic changes during a call. It is mostly true that
network providers will only handle HD Voice on 3G networks though, in
theory, it should be compatible with enhanced 2G networks.
This Manual:
The firmware used on the DHY-04HD is identical to the DHY-04G, so
throughout this manual rather than in each case referring to the
‘
DHY-04G and the DHY-04HD
’ we use just ‘
DHY-04G/HD
’ and the text,
figure, or screenshot will also refer to the DHY-04HD as well. There is only
one specific difference on the Home & Dialler pages from the webserver
where the call state will indicate a normal or an HD Voice call.
There is a separate technical spec and approvals info for the cellular
connection for the DHY-04HD.
