I have read the sticky post but still have some question on the wiring part.

I am new to those TTL things. The RS232 to TTL I have here is a little bit different on the pins:

T/R-

T/R+

RXD-

RXD+

GND

VCC

the sticky post have the following connection:

- From PC (TX) to >>> RX (on Seagate)

- From PC (RX) to >>> TX (on Seagate)

- Connect GND and +5V to PC power supply, or similar

so

Q1. which pin should I use from the PC side to connect to RX/TX on Seagate HDD? My device have +/-.

Q2. Should my CR2032 connect to the TTL device's GND and VCC? If the ans is yes, is the + side connect to VCC or the other side? (leaving the GND pin on HDD disconnected)

Any help would be appreciated.

I didn't expect any relationship between a hard disk, an Rs232 (=serial port) link, nor a Cr2032 coin battery.

In which kind of configuration or use do they meet?

And by TTL, do you mean Transistor-Transistor-Logic?

I'm no expert but I think Rx is 'data out' and Tx is 'data in' which would suggest you need a + and a - to make it work. You need to read through the sticky to find the correct wiring for what you have. There are a few pics with wiring there to look at. I went for the simple option and bought a dku-5 cable for £3 off fleabay, didn't need a battery and wiring is documented so it was easy to adapt.

Edited October 21, 200916 yr by TLH