CH1788 ET Overview
In addition, certain applications can be supported by 20 pins.IC Type MODEM indicates this electrical device is a telecom IC.
CH1788 ET Features
20 pin count

CH1788 ET Applications
There are a lot of Cermetek MicroElectronics, Inc
CH1788 ET Modems ICs & Modules applications.

Desktop PC
Notebook
Pocket PC
Desktop radio
Clock radio
Tuner
Portable radio
Car radio
Satellite radio receiver
Shortwave receiver

Surface Mount	YES
Number of Terminals	22
ECCN (US)	EAR99
HTS	8542.39.00.01
Main Category	Chipset
Maximum Data Rate Range	2.4Kbps to 20Kbps
Maximum Data Rate	2.4Kbps
Transmission Media Type	RJ-11
Minimum Operating Supply Voltage (V)	2.7
Typical Operating Supply Voltage (V)	3.3|5
Maximum Operating Supply Voltage (V)	5.3
Typical Supply Current (mA)	51
Minimum Operating Temperature (°C)	-40
Maximum Operating Temperature (°C)	85
Standard Package Name	LCC
Supplier Package	PLCC
Mounting	Surface Mount
Package Height	6.48
Package Length	24.13
Package Width	24.13
PCB changed	20
Lead Shape	J-Lead
RoHS	Compliant
Package Shape	SQUARE
Manufacturer	Cermetek Microelectronics
Part Status	Obsolete
Terminal Position	DUAL
Terminal Form	J BEND
Number of Functions	1
Terminal Pitch	1.27 mm
Reach Compliance Code	unknown
Pin Count	20
JESD-30 Code	S-PDSO-J22
Temperature Grade	INDUSTRIAL
Data Rate	2.4 Mbps
Seated Height-Max	7.366 mm
Telecom IC Type	MODEM
Modulation Technique	DPSK/FSK/QAM
Power Supply Type	Analog
Width	24.13 mm
Length	24.13 mm
RoHS Status	Supplier Unconfirmed