RadioShack 22-168

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RadioShack 22-168
Rs 22 168 angle.png
Status supported
Source code serial-dmm
Counts 2000
IEC 61010-1 Unspecified
Connectivity RS232
Measurements voltage, current, resistance, capacitance, continuity, diode, logic, frequency, hFE
Features data hold, min/max, 10 reading memory

The RadioShack 22-168 is a 2000 counts handheld digital multimeter with RS-232 connectivity.


  • 3 1/2 digit ADC with bandgap reference: Maxim MAX130CPL (datasheet) (marking: "Maxim MAX130CPL 0138-3 C10039")
  • CPU: Metex KS57C2016 (Samsung KS57C2016 4-bit microcontroller with custom Metex firmware) (marking: "Metex 93D3 KS57C2016-02 410")
  • ?: Metex 9005 (marking has ST logo: "Metex 9005 MET7ACS 92A32792BA")
  • Crystal: 4.1856MHz crystal
  • 555 timer: Intersil ICM7555CBA (datasheet) (marking: "H 7555 CBA L405")
  • Quad analog switch/quad multiplexer: Motorola 14066B (datasheet) (marking: "14066B XAC334")
  • Quad 2-input NAND gate: GD4011BD
  • Optoisolator: Lite-ON LTV-817
  • Unidentified ICs: Two ICs, which appear to be SSOP8 packages are hidden behind black goo. The purpose of the goo is unknown.



See Device_cables#Metex_5-pin_RS232_cable.


See Multimeter_ICs#Metex_14-byte_ASCII.