I'd like to know if it is possible to connect directly the output RSR 232 of the laptop by wire with the input of the HANDCONTROLLER of the PANOHEAD MERLIN?
No, it is not possible to connect directly
You need an RS232-TTL adapter in between.
The simplest and cheapest way of assembling such an adapter is to start with the Tronisoft 4201 RS232-TTL module:http://www.tronisoft.com/4201.php
Then add two 220 ohm resistors and a 4-way RJ11 cable - as shown/described here:http://www.autopano.net/forum/p30622-2008-10-12-15-57-21#p30622