The DHY-04HD HDS is a 1U rackmount single Voice Hybrid which is 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, it 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.

• Five band UMTS/HSPA+850 / 900 / 1800 / 1900 / 2100MHz
• Rear panel 2G GSM or 3G SIM card insertion
• Ethernet web server control and configuration
• Front panel speed-dial buttons with redial
• Signal strength LED display
• LEDs for SIM enabled and GSM network availability
• Automatic operation
• Combined AES/EBU and analogue input and output

It is 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-04HDS 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.

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. It is ideal for broadcasters and journalists providing a frequency response up to 7kHz (twice that of a normal GSM or POTS connection).

The Use of HD Voice is Dependent on 3 Criteria
• The method has to be supported by the network, (and this may be limited by your contract) and when different networks are involved in the call, the interoperability between the networks
• 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
• The signal quality can vary during the call. Normally the hybrid will be used in a fixed location (even OB trucks are normally stationary), so the position of the antenna can be refined for best signal quality. However the far end may be from a cellular phone, so may vary in quality and which can lead to dynamic bandwidth changes during a call. It is mostly true that network providers will only handle HD Voice on 3G networks though, in theory, it should aldo be compatible with enhanced 2G networks