Operating Instructions ST 20
Contents
1. Change the actual setting with the frequency keys and Save the new setting with the signal interrupter key Toggle through further items of the setup menu with the frequency keys 49 and Leave the setup menu by pressing the pulse key The setup menu of the ST 20 offers the following choices The test signal is a steady tone Continuous PulseO ContinuousPulse1 The test signal is a pulse tone Pressing the signal key interrupts the test Inter Present signal Inter Present Pressing the signal key presents the test signal ST20 Fe 11a doc 18 851 307 2 11 11 Flashtext Time L Flashtext Time S Frequence Roll 0 Frequence Roll 1 TransducerchangeO Transducerchange1 Language select ST20 Fe 11a doc Operating Instructions ST 20 The Flashtext time Function description of a pressed key on the LCD Display is long app 3 seconds Setting for inexperienced users The Flashtext time Function description of a pressed key on the LCD Display is short app 1 seconds Setting for experienced users Pressing the frequency key or at the lowest 250 Hz or highest 8 kHz resets the frequency to 1 kHz Pressing the frequency key or at the lowest 250 Hz or highest 8 kHz frequency rolls the frequency over to the highest 8 kHz or lowest 250 Hz frequency Changing between AC BC or FF with key OG keeps the actual test frequency unchanged2. ST20 Fe 11a doc 25 851 307 2 11 11 M 4 Operating Instructions ST 20 MAICO Checklist for Subjective Audiometer Testing Clean the ear and head cushion Instru ment Untangle all lines when necessary Are the headphone cushion in good condition Ma ufa cturer If not gt replace Are plugs and leads in good condition undamaged Serial NO Are all controls working properly 15 the Patient Response Key working properly if available Exa mM ner Check batteries and renew if necessary Test Signal Quality All the test frequencies in the below table indicate typical hearing level and can be changed when necessary Masking B for Buzz tone for Noise V for signal distortion S for switching masking noise Righttar evel kHz 025051 p pap B 025051 p B p g kHz Bogi S S ll L been j _ __ f ll Lo j f j _ LL LL LL f j 1 di born j When noise B G V or S is blocked inform the service center When the test tone is heard at the masking ear contact the service center Air Conduction Audiogram kota Ear kHz p25051n 2 B M 6 BERI E E E CE EE Left Left Earpiec a Earpiec Right Right Earpiec BE Earpiec ox x xx Should is the last measurement of the patient For inverted measurement please reattach the headphone
3. ST20 Fe 11a doc 7 851307 2 11 11 M 4 Operating Instructions ST 20 MAICO 4 Test procedure 4 1 Air Conduction AC test 4 1 1 Screening test The patient should sit at a distance of at least 1 m from the device Before putting on the headphones set the slider level control at 10 dB Eliminate any obstructions which will interfere with the placement of the earphone cushions on the ear i e hair eyeglasses Ensure the headphones are put on correctly Red side on the right blue side on the left Adjust the headband of the headphones so Picture 6 Headphone that the receivers are at the correct height the sound output grid exactly facing the ear channel Place the audiogram paper on the two holding pins Press the key until the according LED lt lights for AC Press the red key for the right ear or the blue key for the left ear Controls and displays D Power switch AC FFA Masking Pulse SISI Right ear red Lett ear blue Signal interrupter key 9 Level slide control Signal presentation 2 Audiogram form Light point B Frequency down WOW Frequency up Picture 7 Front panel of ST 20 with controls and displays ST20 Fe 11a doc 8 851307 2 11 11 Operating Instructions ST 20 MAICO Set the slider level control at 30 dB Test through the frequencies After switching on the freque
4. MAICO Diagnostic GmbH MAICO Operating Instructions MAICO ST 20 MAICO Diagnostic GmbH Salzufer 13 14 D 10587 BERLIN Tel 4 49 30 70714650 Fax 49 30 70714699 M 4 Operating Instructions ST 20 MAICO Table of Contents Page De MIU NOY re NR u 3 eg ea ne ee oe CT 4 3 Getting started 2 eee cece cence III I Im nennen nnne nennen nnn nnn 6 4 1 Air Conduction AC 1 5 8 SOS 8 4 1 2 Hearing Threshold 1 I 9 4 1 3 Masking in the air conduction 10 4 2 Test of the Bone Conduction BC ST 20 BC and ST 20 SISI only 11 4 2 1 Hearing threshold 1 1 11 4 2 2 Masking in the bone conduction measurement ST 20 BC and ST 20 SISI 11 4 3 Tests in Free field FF with loudspeaker Optional 12 4 3 1 Reflex and Direction Tests for free field measurements 12 4 4 How to run the SISI Test ST 20 SISI only 13 4 4 1 Preparation of the 1 Hee 13 4 4 2 Training of the Patient mene 13 5 Recommended 15 6 Care and maintenance of the 16 7 Trouble shooting IRR
5. Changing between AC BC or FF with key resets the test frequency to 1 kHz Choose your language for the text on the LCD Display Possible selections are English French Spanish and German 19 851 307 2 11 11 M 4 Operating Instructions ST 20 MAICO 9 Technical Data and Accessory The ST 20 audiometer is an active diagnostic medical product according to the class lla of the EU medical directive 0123 93 42 EEC Audiometer Class A 4 according to EN 60 645 1 Test Frequency 250 Hz 500 Hz 1 kHz 2 kHz 3 kHz 4 kHz 6 kHz 8 kHz Sound Pressure Level 5 dB level steps AC with earphone Holmco type 8103 B 26 10 dBHL 100 dBHL for 250 Hz 6 kHz 8 kHz to 90 dB BC with bone conduction receiver B 71 only ST 20 BC SISI 10 dBHL 70 dBHL for 250 Hz 35 dB 6 kHz 40 dB 500 Hz 4 kHz 60 dB kHz 65 dB FF with loudspeaker optional 10 dBSPL 90 dBSPL measurement 10 cm away from the ear Test Signal Pure tone or pulse tone Masking Signal broadband white noise Masking Level automatic AC 15 dB lower as the actual test level BC 15 dB higher as the actual test level Modulation pulse tone on off modulation time 0 5 s SISI test 5 dB dB 2 dB conditioning 1 dB test Modulation time 4 8 0 2 s Interrupter Interruption or presentation of the test signal changeable via setup menu Power Supply 230V 50 Hz 10 Power Consumption 4VA Device Fuses 50 mA semi time lag
6. internal Warm up time gt 10 min after power on Environment conditions 15 35 C operation 5 50 storage Maximum humidity 90 96 storage and operation Dimensions WxHxb 29x22x6cm Weight 1 9 kg Geba ST20 Fe 11a doc 20 851 307 2 11 11 M 4 Operating Instructions ST 20 MAICO Connectors Connection Specification amp serial PC Interface RS 232 Patient response switchsleeve ground tip input RI 100 Loudspeaker sleeve2ground tip output Zo 80 0 3 5 Bone conductor BC sleeve ground tip output Zo 80 06 3 5 Headphone AC right red sleevezground tipzoutput 26 80 00 3 5 Vrms Headphone AC left blue sleeve ground tipzoutput Z5280 U9523 5 Mains socket left rightzmains 230 V 50 Hz Picture 30 rear of ST 20 with connection plugs Calibration values AC Receiver Holmberg 8103 26 Force 13 16N Reference equivalent threshold sound pressure level according to ISO 389 1 with Coupler according to IEC 303 Frequency Hz dB re 20 uPa sound damping dB Geba ST20 Fe 11a doc 21 851 307 2 11 11 M 4 Operating Instructions ST 20 MAICO Calibration values BC Receiver Radioear B 71 Force 4 9 5 9 Reference equivalent radiation threshold force level according to ISO 389 3 minimum maximum Frequency Hz dB re 1 Calibration values FF Loudspeaker Part No 801503 R
7. 17 8 Individual Setup of the ST 20 18 9 Technical Data and Accessory 20 10 Warranty Maintenance and After Sales 24 11 Safety Regulations mmn 25 11 1 Electrical Safety mmm 25 11 2 Measuring security nnne nere 25 ST20 Fe 11a doc 1 851307 2 11 11 Operating Instructions ST 20 11 3 Device control mm m mmn 25 IIE259 0 719 25 11 5 Patient NR 25 ST20 Fe 11a doc 851307 2 11 11 M 4 Operating Instructions ST 20 MAICO 1 Introduction Thank you very much for purchasing a quality product from the MAICO family This ST 20 audiometer is manufactured to meet all quality and safety requirements and has been certified with the CE symbol according to Medical Directive 93 42 EEC In designing the ST 20 we placed particular importance in making it a user friendly device meaning its operation is simple and easy to understand And because ST 20 functions are software controlled upgrading later to new extended measurement functions will be simple and inexpensive That means that you have invested in a device that will adjust to your future needs This user manual should make it as easy as possible for you to become familiar with the functions of the ST 20 Please open out the flap of illustrations on the la
8. If the frequency difference between Should and 5 for one ear averages more than 10 dB contact the SERVICE CENTER Bone Conduction Audiogram Righttar evel Lefttar OS S kHz 025051 R 4 Oesp p p dBHV dBHV If the frequency difference between Should and 5 for one ear averages more than 10 dB contact the SERVICE CENTER ST20 Fe 11a doc 26 851 307 2 11 11 M Operating Instructions ST 20 MAICO Specifications are subject to change MAICO Diagnostic GmbH Salzufer 13 14 1058 Berlin Telefon 49 30 70 71 46 50 Telefax 49 30 70 71 46 99 e mail export maico biz MAICO Internet www maico biz ST20 Fe 11a doc 27 851 307 2 11 11
9. Retrocochlear neural hearing damage 15 represented by results 25 96 a cochlear inner ear defect by values 70 96 Press the SISI key to leave the SISI test ST20 Fe 11a doc 14 5dB COM of 0 Picture 20 patient answer 5dB 1 of 1 Picture 21 valid answer 3dB 0 of O Picture 22 cond 3 dB 2dB 0 of O Picture 23 cond 2 dB SISI 0 of 0 Picture 24 start SISI Test 5151 O 8 of 12 Picture 25 Example SISI Test 10 of 20 2000Hz Picture 26 result SISI test 100960f 9 2000Hz Picture 27 result SISI test with manual stop 851 307 2 11 11 M 4 Operating Instructions ST 20 MAICO 5 Recommended literature Audiometric Interpretation A Manual of Basic Audiometry Lloyd Lyle L and Harriet Kaplan Baltimore University Park Press 1980 Auditory Disorders A Manual for Clinical Evaluation Jerger Susan and James Jerger Boston College Hill Press 1981 Handbook of Clinical Audiology Katz Jack Baltimore William amp Wilkins 1994 s Audiology Desk Reference Roeser Ross J New York Stuttgart Thieme 1996 Auditory Diagnosis Silam Shlomo and Carol A Silvermann San Diego London Singular Publishing Group 1997 Geba_ST20 Fe 11a doc 15 851 307 2 11 11 Operating Instructions ST 20 MAICO 6 Care and maintenance of the instrument Disconnect the mains plug before cleaning To dean the instrument headphones bone conduction receiver loud
10. a Picture 11 LCD display masking level of 35 dBHL To disable masking press key again If your ST 20 has the optional LCD display for a short time a corresponding message is displayed see picture 11 Picture 10 LCD display Test and masking level Attention When the channel R L is changed or the acoustic transducer or BC cp FF Kis changed the frequency is automatically set to the starting point of 1 kHz This function can be turned off in the setup menu see chapter 8 If the acoustic transducers or the channel R L cannot be selected set the level control to 10 dB If the maximum permitted level the headphones bone conduction receiver or loudspeaker is exceeded the test signal will not increase The corresponding light point in the audiogram form flashes to indicate that the level limit has been reached Geba ST20 Fe 11a doc 10 851 307 2 11 11 Operating Instructions ST 20 4 2 Test of the Bone Conduction BC ST 20 BC and ST 20 SISI only 4 2 1 Hearing threshold test In the hearing threshold test the hearing threshold of the patient is measured in ai comparison with the normal hearing threshold for bone conduction Differences in the measured hearing threshold for air conduction see 4 1 2 give indications of problems in the middle ear Picture 12 Bone conductor Set the slider level control to 10 dB Place the bone conduction receiver so that
11. are not intended for operation in areas with an explosion hazard 11 2 Measuring security To guarantee that the audiometer works properly the instrument has to be checked and calibrated at least once a year The service and calibration must be performed by an authorized service center In accordance with the regulations of the EU medical directive we will drop our liability if these checks are not done The use of non calibrated audiometers is not allowed 11 3 Device control The user of the instrument should perform a subjective instrument check once a week This check can be done following the list Tor subjective instrument check see next page For your own security you should copy the enclosed list fill it in once a week and store it in your files 11 4 Operation Only skilled personnel Audiologists ENT professionals or other with equivalent knowledge should operate the instrument 11 5 Patient Safety Please note that if connection is made to standard equipment like printers and network special precautions must be taken in order to maintain medical safety Connecting this device to other devices in order to make a system may cause the safety specifications to be invalid It is therefore recommended to insert a galvanic separation between the device and the host computer unless the computer is battery operated or supplied by a medical approved power supply Galvanic separation must fulfil the EN 60 601 1
12. test level of 50 dBHL and a masking level of 65 dBHL Masking on Geba ST20 Fe 11a doc 11 851 307 2 11 11 Operating Instructions ST 20 MAICO To disable masking press key again If your ST 20 has the optional LCD display for a short time a corresponding message is displayed see 50 1000R HL 65 picture 1 5 Picture 14 LCD Display Continue as described before under 4 2 1 Test and masking level bone conduction test Put the headphone with the according side PE on the opposite ear with the other side on the Masking off cheek bone in front of the test ear Adjust the Picture 15 LCD Display headband so that the headphone sits at the Masking off right height to the opposite ear the sound grid exactly facing the auditory passage see chapter 4 1 1 The marking for bone conduction with masking should be done with the symbols on the right and on the left in the audiogram form For hygienic reasons it is important to clean the bone conduction receiver see chapter 6 4 3 Tests in Free field FF with loudspeaker optional 4 3 1 Reflex and Direction Tests for free field measurements The test with babies and infants is performed with pulsed tones Set the level control at 10 dB Select FF by pressing key until the lamp under the symbol lights Press the pulse key The sound is switched on and off periodically The green signal presentation LED flashes When
13. test room must be at normal temperature usually 15 C to 35 C and the instrument should be switched on about 10 minutes before the first measurement to guarantee precise measuring results If the device has been cooled down e g during transport please wait until it has warmed up to room temperature Insert the instrument plug of the mains cord into the mains socket on the rear of the instrument Insert the other end of the mains cord into a 230 V shock proof socket Connect the right red headphone to the correspondingly labelled socket and the left Blue headphone socket at the rear of the device If your device is equipped with a patient response switch plug it to socket The LCD display is connected to socket and screwed into the ST 20 The bone conduction receiver P of ST 20 BC and ST 20 SISI is connected to socket O The optional loudspeaker K is connected to socket 4 tb O MULTI PORT Picture 4 rear panel of ST 20 with connectors ST20 Fe 11a doc 6 851307 2 11 11 M 4 Operating Instructions ST 20 MAICO Slide the level control completely to the top and turn on the device with switch 5 in the audiogram form d light up After the test the 1 kHz light point in the audiogram form and the green signal presentation LED light up only in interrupter mode It in dicates that the test tone can be heard If the green signal presentation LED does not lig
14. eference sound pressure level Frequency Hz re 20 uP Geba ST20 Fe 11a doc 22 851 307 2 11 11 M 4 Operating Instructions ST 20 MAICO Standard accessories 1 air conduction receiver Holmco 8103 B 26 1 pad of audiogram paper 50 sheets mains cord 1 bone conduction receiver B 71 ST 20 BC ST 20 SISI only 1 patient response switch ST 20 SISI only 1 LCD display ST 20 SISI only Optional accessories Carrying case for the device and accessories Part No 705050 Loudspeaker Part No 801503 Headphone padding for children Part No 8698847632 Patient response switch Part No 80101249 LCD display for level and frequency Part No 80 20 90 Consumables 5 pads of audiogram paper 50 sheets Part No 861001 ST20 Fe 11a doc 23 851 307 2 11 11 M 4 Operating Instructions ST 20 MAICO 10 Warranty Maintenance and After Sales Service The MAICO ST 20 is guaranteed for 1 year This warranty is extended to the original purchaser of the instrument by MAICO through the distributor from whom it was purchased and covers defects in material and workmanship for a period of one year from date of delivery of the instrument to the original purchaser The ST 20 may be repaired and serviced only by your dealer or by a service center recommended by your dealer We urgently advise you against attempting to rectify any faults yourself or commissioning non experts to do SO In the event of repair during the guaran
15. es The test tone is adjusted by means of a slider control for the level in 5 dB steps and the frequency adjustments are made by electronic push buttons The particular value of frequency level is indicated by a red light point in the audiogram field In addition the optional LCD display picture 2 shows level and frequency standard accessory of ST 20 SISI The ST 20 offers eight test frequencies from 250 Hz up to 8 kHz and a range of 10 dBHL up to 100 dBHL for air conduction Picture 1 Front panel of ST 20The bone conduction measurement with the ST 20 BC can be carried out with seven test frequencies from 250 Hz to 6 kHz and a range of 10 dBHL up to 70 dBHL requested the test signal can automatic be masked with the opposite headphone The optional loudspeaker delivers test levels from 10dBHL to 90 dBHL for free field measurement at a distance of 10 cm Picture 1 Front panel of ST 20 ST20 Fe 11a doc 4 851307 2 11 11 MAICO In addition to the features found in the ST 20 BC the ST 20 SISI offers the SISI Test diagnostic function For this purpose the ST 20 SISI is equipped with a patient response switch and a LCD display which shows level and frequency or the SISI test information and the test score Picture 2 LCD Display The patient response switch is a standard accessory of the ST 20 SISI but is offered as an option on the other models Whenever the patient hears the test tone he pr
16. esses the patient response switch The patient response is indicated by the flashing of the red light point The audiometric value can easily be marked on the audiogram paper Picture 3 Patient response switchWhen you push any key of the ST 20 a message Flashtext will be shown for a short time on the optional LCD Display i e Masking on This message gives information about the function or status of the key This feature makes it easy for inexperienced users to get familiar with the ST 20 The audiometer is designed to be extremely service friendly Automatic test programs make Operating Instructions ST 20 M MAICO R L e 22 Picture 2 LCD Display Picture Patient response switch trouble shooting and the yearly check as easy as possible ST20 Fe 11a doc 5 851 307 2 11 11 Operating Instructions ST 20 MAICO 3 Getting started The ST 20 should be operated in a quiet room so that the audiometric examinations are not influenced by outside noises However the sound insulation muffs of the headphones perform so well at excluding sound the instrument can be used in noisier environments Electro medical instruments which emit strong electromagnetic fields e g microwaves radiotherapy devices can influence the function of the audiometer Therefore the use of these instruments is not allowed in close proximity to the audiometer The
17. ht up and the 1 kHz light point flashes the level control needs to be set at 10 dB Due to the built in protective device the test signal has been faded out automatically p RU d men Patient safety The built in protective device makes sure that during the initialization or when changing the channel as well as from air conduction to bone conduction or free field the patient s ear is protected from high sound exposure The protective device is triggered by sound levels more than 50 dBHL and fades out the test sound This is indicated by the flashing of the light points in the audiogram form and green signal presentation LED In this case set the level control to the upper position and when the light point stops flashing the green signal presentation LED lights up and the test sound is faded in If during the initialization of the device the 250 Hz 500 Hz light points start to flash the device has detected an error In this case contact customer service see chapter 10 Calibration of the device The instrument headphones bone conduction receiver ST 20 BC and ST 20 SISI only as well as the optional loudspeaker match one another and have the same serial number e g 6631520 It is not allowed to use the device with other transducers If one of the acoustic transducers is replaced the instrument must be recalibrated The use of non calibrated audiometers leads to incorrect measurements
18. it lights up the test tone can be heard Position the loudspeaker about 10 cm away from the ear to be tested Present the test tone by pressing the switch at the rear of the loudspeaker Increase the level control 9 slowly When the child shows a reaction e g turns the head enter the measurement on the audiogram form with the remark loudspeaker testing Use the frequency keys 3 to select higher or lower frequencies Picture 16 Loudspeaker ST20 Fe 11a doc 12 851 307 2 11 11 M 4 Operating Instructions ST 20 MAICO 4 4 How to run the SISI Test ST 20 SISI only The SISI Short Increment Sensitivity Index test provides a measurement in the supraliminal intensity area It offers additional information to the hearing thresholds measured in sections 4 1 2 and or 4 2 1 Thereby it is possible to distinguish between sensory inner ear and neural auditory nerve hearing damage The SISI test is started by pressing the SISI key To train the patient to the SISI test louder increments of 5 2 and 1 dB are presented to the 1007 SF patient before the test The test tone is increased CHER by 1 dB for a period of 0 2 seconds every 4 8 bi seconds R L Whenever the patient hears the increment he she Picture 17 SISI Display presses the patient response switch The SISI test information and the test score are sho
19. ncy is automatically set to 1 KHz Start at 1 kHz set the higher frequencies first then the low frequencies Use the right key to select the higher frequencies and use the left key 8 to select the lower frequencies Use the interrupter key to interrupt the test tone The green signal presentation LED 2 49 should extinguish If the patient hears the test tone the particular value is displayed by a light point in the audiogram field and should be marked on the audiogram paper The correct markings are O red right and X blue left If all tones are heard it can be assumed that the hearing loss if any is only minimal For hygienic reasons it is important to clean the ear cushions of the headphone see chapter 6 4 1 2 Hearing Threshold Test In the hearing threshold test the hearing threshold of the patient is measured in comparison with the normal hearing threshold for air conduction The test Is started on the ear with better hearing Set the slider level control 9 to 10 dB Using the key or choose the ear that hears better Use the key 3 to set the test frequency at 1 kHz For further preparation see 4 1 1 screening test nstruction to the person being tested Whenever the test tone is just audible the patient should raise their hand or press the patient response switch Picture 8 Controls of ST 20 Increase the test level with the slider level control 9 gradually u
20. ntil the patient indicates that he she can Just hear the test tone ST20 Fe 11a doc 9 851307 2 11 11 Operating Instructions ST 20 Press the interrupter key amp and mark the light point on the audiogram form Set the slider level control back to 10 dB select the next frequency increase the level again Test through the other frequencies in the same way Choose with key or the poorer ear and repeat the hearing threshold test 4 1 3 Masking in the air conduction measurement In the air conduction threshold measurement the opposite ear must be masked if a larger difference between both ears appears The masking signal is a broad band noise which will be selected automatically 15 dB lower than the actual hearing level setting The masking signal is applied to the opposite ear through the air conduction headset Opposite ear describes the current not tested ear if the left ear is tested the right ear is the opposite ear This Picture 9 LCD display masking signal masks the test tone and prevents a Masking on detection of the test signal through the better ear Press key to enable the masking If your ST 50 4000R HL 35 20 has the optional LCD display for a short time a corresponding message is displayed see picture 9 Later the actual test level is displayed on the left and the masking level on the right of the LCD display Example picture 10 shows a test level of 50 dBHL and
21. pprox 1 5 seconds During this period the patient may respond If he she answers too early or too late the answer will not be accepted by the ST 20 When the patient presses the response switch the examiner will see a black box on the display see picture 20 The number of detected increments is counted and shown on the display Furthermore the number of presented increments is shown s picture 21 When you are sure that the patient has understood the object of the test press the SISI key again The modulation level will be reduced to 3 dB If the patient has understood this part of the test also press the SISI key amp The modulation level will be reduced to 2 dB f the patient has understood the test up to here press the SISI key amp again to begin the SISI test The LCD display indicates SISI see picture 24 and the modulation level is adjusted to 1 dB Now 20 increments will be presented to the patient and the examiner can follow the test on the LCD display see example picture 25 The test will end automatically after 20 presented increments The number of detected increments is counted and indicated as a percentage see picture 26 The percent result and the test frequency are entered in the middle of the audiogram form you are sure that the result of the test is stable you can interrupt the test at any time by pressing the pulse key The result is then indicated accordingly picture 27
22. pter operation press the SISI key longer than 3 seconds Are the acoustic transducers connected to the correct socket 15 key in the right position s the lead connecting the headphones or the loudspeaker loose or defective If your instrument still does not work properly after this short check please consult your dealer or send the instrument to your dealer or our service centre see also chapter 10 Geba ST20 Fe 11a doc 17 851 307 2 11 11 Operating Instructions ST 20 MAICO 8 Individual Setup of the ST 20 Only with optional LCD Display or ST 20 SISI possible The ST 20 is configured to meet most requirements But it is also possible to setup some functions of the ST 20 to your individual needs These changes will be stored in the ST 20 even after you switch it off until you change it again in the setup To get into the setup menu of the ST 20 press the red key and switch on the instrument with the power switch Keep the red key 6 pressed until you see on the LCD Display the text ST 20 After releasing the red key the message User menu and then the text shown in picture 29 appears on the LCD Display Picture 29 Setup You can toggle between the different items of Continuous pulse the setup menu using the frequency keys and 4 Select a particular item by pressing the signal interrupter key You see the actual setting flashing on the left of the LCD Display
23. speaker use a soft cloth dampened with little warm soapy water or washing up liquid no alcohol or spirits should be used The headphone cushion and the ear cushions of the headphone Holmco 8103 can be detached for cleaning Please proceed as shown in picture 28 To remove the ear cushion first remove the rubber ring To assemble the cleaned or changed ear cushion start at the rounded location of the headphone During cleaning please ensure that no liquid runs into the switches level control headphone capsules or loudspeaker openings Picture 28 changing of the ear cushions of Holmco 8103 ST20 Fe 11a doc 16 851 307 2 11 11 M 4 Operating Instructions ST 20 MAICO 7 Trouble shooting If you should find that your instrument is no longer working properly during a test run please check the following points The acoustic transducers cannot be selected Level control 9 must be set at 10 dB and the required key pressed Diodes do not light up and there is no light point on the audiogram field 7 Is the mains lead plugged in correctly Is the power switch at the On B position Light point available but test tone is absent Green signal presentation LED 549 does not light Level control 9 must be set at 10 dB position Press signal interrupter key amp When the LED lights up and the tone is avallable the device works in presenter mode For switching over to interru
24. st page The description of the position e g of controls displays and connections found again in the text will make it easier for you to learn how to operate the ST 20 If you have problems or have ideas for further improvements please get in touch with us Simply call Your MAICO team ST20 Fe 11a doc 3 851307 2 11 11 Operating Instructions ST 20 2 Description The audiometer ST 20 is a quick testing screening audiometer for audiometric tone examination of babies children and adults It is a handy semi automatic audiometer that is easy to operate facilitates quick uncomplicated detection of hearing defects It has been designed for use in the office of the paediatrician and in general practice in the public health services and in occupational medicine As a result of modern microprocessor technology the ST 20 is very comfortable to use and has a high operating reliability A PC interface for data transfer to a connected computer is available special interface cord required The tests can be performed with a continuous or pulsed tone via headphones Masking with the opposite headphone is possible if needed In addition bone conduction measurement can be done with the ST 20 BC and ST 20 SISI Free field transmission is possible via the optional loudspeaker Moreover the ST 20 SISI offers the opportunity to conduct the SISI test The frequency and intensity level are set without any electronic static nois
25. tee period please enclose evidence of purchase with the instrument In order to ensure that your instrument works properly the ST 20 should be checked and calibrated at least once a year This check has to be carried out by your dealer When returning the instrument for repairs it is essential to send the headphones as well Send the device to your dealer or to a service center authorized by your dealer Please include a detailed description of faults In order to prevent damage in transit please use the original packing if possible when returning the instrument Within the European Union it is illegal to dispose electric and electronic waste as unsorted municipal waste According to this all MAICO products sold after August 13 2005 are marked with a crossed out wheeled bin Within the limits of Article 9 of DIRECTIVE 2002 96 EC on waste electrical and electronic equipment WEEE MAICO has changed their sales policy To avoid additional distribution costs we assign the responsibility for the proper collection and treatment according legal regulations to our customers Geba ST20 Fe 11a doc 24 851 307 2 11 11 M 4 Operating Instructions ST 20 MAICO 11 Safety Regulations 11 1 Electrical Safety The ST 20 audiometer is constructed to comply with protection class Il of the international standard IEC 601 1 EN 60601 1 Protection from an electric shock is ensured even without the system earth connection The instruments
26. the flat circular side of the transducer Y is placed on the mastoid at the noticeable ledge of the cranial bone behind the auricle The other side of the headband is placed in front of the opposite ear Select BC by pressing key until the lamp under the symbol lights Perform the test the same way as for air conduction see 4 1 2 Enter the measurements for all frequencies on the form connect all points with dotted lines marked on the audiogram form as follows gt right and lt left 4 2 2 Masking in the bone conduction measurement ST 20 BC and ST 20 SISI In the bone conduction threshold measurement the opposite ear must be masked if a difference of at least 10 dBHL between both ears appears The masking signal is a broad band noise which will be selected automatically 15 dB higher than the actual hearing level setting The masking signal is applied to the opposite ear through the air conduction headset Opposite ear describes the current not tested ear if the left ear is tested the right ear is the opposite ear This masking signal masks the test tone and prevents a detection of the test signal through the non tested ear Press key to enable the masking It your ST 20 has the optional LCD display for a short time a corresponding message is displayed see picture 13 Menor A Later the actual test level is displayed on the left and the masking level on the right of the LCD display Example picture 14 shows a
27. wn on the LCD display The test will end automatically after 20 presented increments 4 4 1 Preparation of the Test Set the test frequency with the frequency keys or d For the test you should choose the frequency level where the maximum bone conduction hearing loss was measured see 4 2 Set the test level with the level control slider The volume is set to 20 dB above the individual hearing threshold measured under section 4 2 It must reach at least 60 dBspl The patient must be instructed You will now hear a continuous tone Every time it becomes louder immediately push the key 4 4 2 Training of the Patient Only with careful training during the following eT ONT conditioning phase can a valid test result can be 5151 Conditioning achieved Picture 18 start display The SISI test is started by pressing the SISI key The LCD display indicates for approx two 5dB LI O of 0 seconds the text shown in picture 18 Then the following text is shown on the LCD display see picture 19 The left figure indicates the current modulation level Initially the value is 5 dB That means the patient is presented with a Picture 19 cond 5 dB ST20 Fe 11a doc 13 851 307 2 11 11 Operating Instructions ST 20 MAICO continuous tone which is briefly increased every 4 8 seconds e g 60 dBHL to 65 dBHL This effect is shown on the LCD display by a note The white small box appears for a
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