TechnoTrend TT-connect CT2-4650 CI
- USB interface: Cypress CY7C68013A-56LTXC
- Demodulator: Silicon Labs Si2168-A20
- Tuner: Silicon Labs Si2158-A20
- CI chip: CIMaX SP2HF
The driver is in media_tree and can be built into older kernels using media_build. Inclusion probably to kernel 3.18.
Manufacturer also provides non open source drivers: 
Bus 002 Device 004: ID 0b48:3012 TechnoTrend TT-connect CT2-4650 CI
[136379.859951] dvb-usb: found a 'TechnoTrend TT-connect CT2-4650 CI' in warm state. [136379.859979] dvb-usb: will pass the complete MPEG2 transport stream to the software demuxer. [136379.860109] DVB: registering new adapter (TechnoTrend TT-connect CT2-4650 CI) [136380.066503] i2c i2c-0: Added multiplexed i2c bus 1 [136380.066505] si2168 0-0064: si2168: Silicon Labs Si2168 successfully attached [136380.069052] si2157 1-0060: si2157: Silicon Labs Si2157/Si2158 successfully attached [136380.283682] sp2 0-0040: CIMaX SP2 successfully attached [136380.283688] usb 1-1.3.3: DVB: registering adapter 0 frontend 0 (Silicon Labs Si2168)... [136380.284024] Registered IR keymap rc-tt-1500 [136380.284126] input: IR-receiver inside an USB DVB receiver as /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.3/1-1.3.3/rc/rc0/input27 [136380.284160] rc0: IR-receiver inside an USB DVB receiver as /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.3/1-1.3.3/rc/rc0 [136380.284162] dvb-usb: schedule remote query interval to 150 msecs. [136380.284163] dvb-usb: TechnoTrend TT-connect CT2-4650 CI successfully initialized and connected. [136380.284177] usbcore: registered new interface driver dvb_usb_cxusb [136386.529709] dvb_ca adapter 0: DVB CAM detected and initialised successfully
The firmware for the tuner is the same as for TechnoTrend TT-TVStick CT2-4400#Firmware
The demodulator needs a firmware that can be extracted from the Windows drivers. File ttConnect4650_64.sys should be extracted from the driver package (MD5 sum below).
Then the firmware can be extracted:
dd if=ttConnect4650_64.sys ibs=1 skip=273376 count=6424 of=dvb-demod-si2168-a20-01.fw
IR Remote Control
The supplied remote control is supported by the driver.