DIY: serial cellphone data cable (20pin samsung connector)

[gdgd]

Hi,

Since the year 2011 the serial data cable 8**) is sold out in the whole
world. -So I want to solder this serial data cable by myself (I want to
use the data cable for my GT-E1150 handy).

at the pinout description ..

http://pinoutsguide.com/CellularPhones-P-W/samsung_d800_pinout.shtml

I've found the following annotation:
"Pins 2,7 shorted and connected to +5V supply in serial (flash) cable."

Question:
Is pin 2,7 related to the RS232 or to 20pin connector ?
-What is the purpose when connecting pin2 to pin7
and what is the purpose to connect +5V to 2,7
?

________
/ 1 2 3 4 5\
|  6 7 8 9 |

2 Rxd
3 TxD
5 GND
7 RTS (If Hi, Data can be sent)

8**)
the serial data cable has the model number APCBS21SBE or APCBS21SBEC or APCBS21SBECSTD
http://www.samsung.com/ch/consumer/mobile-phone/mobile-phone/mobile-accessories/APCBS21SBECSTD?subsubtype=data-cable