Finally i’ve got TTL to USB dongle. Here is some photos:

Silicon Labs CP2102 as detected by MacOS

Drivers can be downloaded from the official site.
Driver version 4.1.1 successfully installed under MacOS X Yosemite 10.10.5 (14F27).

$ kextstat | tail -1
  170    0 0xffffff7f832d7000 0x6000     0x6000     com.silabs.driver.CP210xVCPDriver (4.1.1) <90 37 4 3>

driver loaded and we’re got two special character devices under the /dev directory:

$ ls -la /dev/*SLAB*
crw-rw-rw- 1 root wheel 17, 11 Sep 14 23:04 /dev/cu.SLAB_USBtoUART
crw-rw-rw- 1 root wheel 17, 10 Sep 14 23:04 /dev/tty.SLAB_USBtoUART

now we’re should perform loopback test. Short RX and TX pins, and run terminal:

sudo cu -l /dev/tty.SLAB_USBtoUART -s 115200

try to enter some text. Letters should be displayed while each key pressed.
If you’re see typed text all fine and press ~. (tilde and period) to exit terminal.