45
D-0126050 rev 1 -
270+ Operating Manual
PC Interface
Serial Interface:
USB Version 1.1
Information sent:
Tone Audiometry: THL, MCL, ULL (UCL), BC, masked
thresholds and SRT for speech test results for both
ears,
Communication:
Integral talkover facility
Talkover and talkback facility via external headset
6.3.
TONE AUDIOMETRY
Transducer
Outputs:
Left earphone, Right earphone, Bone (L&R) Insert
masking and Freefield
Options:
AC: DD45 earphones (supplied), IP30: Insert
earphones (option)
BC: B-71 bone vibrator (supplied)
Transducer types and
reference levels:
DD45: ISO 389-1, Table 2
IP30: ISO 389-2, Table 1
B-71: ISO 389-3, Table 1
Static headband force:
Headphones: 4.5N
Bone vibrator: 5.4N
Sound attenuation
characteristics:
ISO8253-1, Table 3
Airborne sound from
bone vibrator:
See Br. J. Audiol. 1980, P73-75
Insert Masking
Earpiece
Calibration method:
With 2cc coupler compliant with IEC 126
Test Signals
Frequency:
AC: 0.125
– 8 kHz
BC: 0.25
– 8 kHz
Frequency accuracy:
< 1 %
Distortion:
< 2 %
Output level range:
AC: -10dBHL to 120dBHL maximum
BC: -10dBHL to 70dBHL maximum
FF: Up to 90dB
Level step size:
2 or 5dB
Tone present:
Single, Pulsed, Warble or Continuous
Frequency
Modulation
Carrier frequencies:
125Hz to 8kHz as per pure tones
Modulation waveform:
Sinusoidal
Rising and falling
symmetry:
Symmetrical on linear frequency scale
Modulating frequency:
15.625Hz
Frequency deviation:
+/-10%
Masking
Signals:
Narrow bands at test frequencies
Narrow-band noise
bandwidth:
Meets IEC 60645-1; ANSI S3.6
Speech noise bandwidth:
Meets IEC 60645-2; ANSI S3.6
Reference levels:
Refer to ISO 389-4
Output level range:
90dBHL max (250-4 kHz)
Level accuracy:
Within 3dB
Level Step Size:
2 or 5dB
Synchronous channel (Track/ Lock function)
Clinic Tests/
Special Tests
SISI
Stenger
ABLB (Fowler)
Decay (Carhart Test)
MHA (Master Hearing Aid)
Summary of Contents for 270+
Page 1: ...270 Operating Manual...
