1.TYPE

Dynamic receiver for telephone handset.

2.ELECTRICAL CHARACTERISTICS

2.1 TEST SET UP

Shown in Fig.2

2.2 IMPEDANCE

32 ohm±20%（at 1KHz 100mV sine wave）

2.3 SENSITIVITY

100±2dB S.P.L. （at 1KHz 100mV sine wave）

2.4 DISTORTION

<5% （300…3400Hz）

2.5 FREQUENCY RESPONSE

The frequency response relative to the 1KHz response shall Lie between the upper and lower limits show in Fig.1

3.MECHANICAL DATA

15mm X 3.2mmshown in Fig.3

A. SENSITIBITY

• Set decade resistor R to 32 ohm
• Ser switch S1 to position 1
• Set osc. frequency to 1000Hz
• Set Eg to 0.200 VRMS
• Read the S.P.L. indicator

B. FREQUENCY RESPONSE

• Set decade resistor R to 32 ohm
• Ser switch S1 to position 1
• Set osc. frequency to 1000Hz
• Set Eg to 0.200 VRMS
• Vary frequency from 100 to 5000Hz. The frequency response shall fall within the limits of Fig.1

C. AUDIBLE NOISE

• Set decade resistor R to 0 ohm
• Ser switch S1 to position 2
• Set VISUAL voltage to 0.86VRMS
• Listen to speaker output: It must be free of audible noise （buzzes and rattles）through the 300 to 3000Hz frequency range.
  

4.ENVIROMENTAL TESTS

4.1 GENERAL

After any following test, the response at 1KHz shall not deviate more than ±3dB from the initial value.

4.2 HIGH TEMPERATURE TEST

a. Temperature+65℃±3℃
b. Duration96 hours
c. Duration of recovery2 hours

4.3 LOW TEMPERATURE TEST

a. Temperature-25℃±3℃
b. Duration96 hours
c. Duration of recovery2 hours

4.4 HUMIDITY TEST

a. Relative humidity90-95% at +40℃
b. Duration96 hours
c. Duration of recovery2 hours

4.5 TEMPERATURE CYCLING TEST

a. Temperature cycling diagram
b. Number of cycles4 cycles
c. Duration of recovery

4.6 VIBRATION TEST

a. Vibration direction3 axes
b. Frequency55 Hz
c. Vibration amplitude1.5 mm
d. Duration30 minute in each plane

4.7 DROP TEST

a. Unit only: The receiver shall withstand 10 random drops from a height 75cm to a concrete floor, and no mechanical damage.

b. Fixed in handset: The receiver when properly mounted in a handset, shall withstand 6 random drops from a height of 1.5 meters to a concrete floor, and no mechanical damage, and no change the 1KHz response level.