BSNL STD Locking...

A few days back I figured out that BSNL has blessed my phone with STD facility without me requesting for it!! That perhaps explained why my Feb BSNL bill shot up to Rs 1505/- !! I suspected unsolicited outgoing calls. With the resolve to get the STD facility 'locked' I dialled +91 80 25701000 - my exchange's help desk on these matters. The lady at the other end guided me with some instructions. As and when she was guiding me, I thought "This info could be there in the net". I did a google and to my joy saw those instructions in the net. Here it goes...

FUNCTION	E10B & OCB Exchanges DIAL	EWSD Exchanges DIAL
i) Password Registration	123 xxxx xxxx xxxx :dial twice you r4 digit password	123 0000 xxxx xxxx : your 4 digit password
ii) Allow all Calls	124 xxxx 0
iii) Bar only STD Calls	124 xxxx 1
iv) Bar STD Trunk (180) & Internet (172) Calls	124 xxxx 2
v) Allow NSD, Cellular, Local & Trunk Calls	124 xxxx 3
vi) Bar all Out going Calls	124 xxxx 4
vii) Allow Local but Bar Cellular Calls	124 xxxx 5
viii) Change your Password	123 xxxx yyyy Where, xxxx : Existing Password & yyyy : New Password.