C HAPTER 1 - I NTRODUCTION Fig 1.1 Enclosed Speech Unscrambler The CO363AX-E24 24Vdc Helium Speech Unscrambler has been designed into an enclosed version of the standard COAX helium unscrambler. The enclosure provides protection for the unit when installed in a Hyperbaric Lifeboat (HLB). The unit is supplied with a clear PVC cover that provides extra protection for the unit while it is in storage. The front panel of the cover can be lifted up to allow access to the controls when required. The main function of the HLB Unscrambler is to provide clear, two way voice communications between the diver and a supervisor, using three independent communications circuits – Channel Channel 2 and Channel 3 (chamber. Note Only channel 3 has helium speech unscrambling capability. Channel 3 is able to support two independent HLB Comms boxes. Throughout the manual all channels will be referred to as divers. Channel 1 and channel 2 are commonly placed around the HLB to allow the supervisor to talk to the HLB crew. Divers in saturation breathe a gas mixture of helium and oxygen (Heliox) which distorts the human voice to sound high pitched and difficult to understand. The CO363AX-E24 converts the helium affected speech back to a usable audio source that is easy to understand and communicate with.
Chapter 1 CO-OM-6605 R0 The HLB Unscrambler has round robin functionality that will allow the divers using the unit to communicate with each other. When round robin is switched on, Channel 1, Channel 2 and Channel can communicate with each other. There is a supervisor round robin mode which when enabled will allow the supervisor to communicate with all three channels without using a push to talk (PTT) button. When supervisor round robin is switched off the supervisor will use a PTT button to talk with each channel individually via that channels PTT or all three channels at the same time with the ALL PTT” button. The HLB Unscrambler has a Liquid Crystal Display (LCD) for the user interface that will indicate specific unscrambling parameters such as Depth (msw), Partial Pressure (PPO2), Pitch and Temperature. All of these parameters maybe manipulated individually via the user interface. The HLB Unscrambler is also fitted with a loudspeaker so that the diver’s speech is audible to the supervisor independently of the supervisor’s headset. It is possible to have the loudspeaker switched ON or OFF, as desired.