Specifications

Chapter 2 – SocketModem (MT5600SMI & MT5656SMI)
Multi-Tech Systems, Inc. Universal Socket Hardware Guide for Developers (S000342I) 72
Microphone and Speaker
Microphone Input Option
Note: Applies to the MT5656SMI Voice only.
Speaker Output Option 1
Speaker Output Option 2
Specifications for the Microphone Input
Impedance
>70K ohms
AC Input Voltage Range
1.1V P-P
Reference Voltage
1.35V
Specifications for the Speaker Output from the Codec
Minimum Load
300 Ω
Maximum Capacitive Load
0.01 uF
Output Impedance
10 Ω
AC Output Voltage Range
1.4V P-P
Reference voltage
+1.35 VDC
DC Offset Voltage
± 20 mV
Speaker Output
The speaker output from the codec is coupled to the speaker pin (64) through a 1uF cap and a 33 ohm resistor. The
speaker pin is shared with the call progress monitor which is a digital I/O pin on the DSP that is coupled to the
speaker pin through a 1uF and 3.9K.