2 suited support

A: There is opening bid support for 5-5 or better 2 suited hands 4-7 LTC

3C:  Both RED suits
3D:  Both Majors
Open 2D rebid 3C: Clubs & Hearts
Open 2D rebid 3D: Diamonds & Spades

With Spades & Clubs: Open 1S rebid Clubs
With Both minors: Open 1D rebid Clubs.

B. Opponents open the bidding with 1 of a suit - now all pairings for the remaining suits can be shown as follows

(i) 6-7LTC

2N:                         Highest + Lowest unbid suits
Cue-bid:                  The two highest unbid suits
1N and 3C rebid:      The 2 lowest unbid suits

(ii) 4-5LTC

Jump cue bid in opponents minor  opening:           Both Majors   
3mi: when opened with the other minor:               Shows the minor bid + Spades
3mi when opponents open in a Major:                  Show the minor bid & the unbid major

This caters for all except 'other minor and
Hearts'. In this case use the following sequence:  o'call 1H and rebid 3 minor. Partner, however, cannot be sure this is showing 5-5.
Alternatively: first o'call 1N and rebid 2H shows lowest 2 unbid suits 4-5 LTC - note valid whatever the opening: showing the lowest two unbid suits!

C. Protective position when LHO opened 1 of any suit

Now bidding the lower of your 2 suits cyclically shows the suit and the next higher.
Ex:  1S-P-P-2D red suits; 1H-P-P-1S S+C   etc.
With a fairly balanced hand without 2 suits use Protective Double asking partner to choose his suit.

Notes: If you have a 6+ card single suited hand make a jump in it.  1D-P-P-2H
With a fairly balanced hand with values in the opponents suit cosider 1NT - this is not a strong bid. Partner may make a transfer to take- you out of 1NT. This option means that our multi 1N o'call only applies in 2nd position.

D. Defence to opponents opening of 1NT

We use CDH.
Note this modified in the protective position to show the minor bid and a higher ranking suit or suits. 2 Hearts shows 5+ Hearts and 2S shows 5+ Spades.

Rusinov can be used in 2nd position only to show 2 suits when 4-5LTC by transfering first to the higher ranking suit and then bidding the second suit at your next  bid.

E. Responding to partners' T-O *

With (7)8+ HCP and 2 suits at least 4-4 bid the lower ranking cyclically at the next bidding level.
Important Note: If your RHO has passed and you hold the lowest 2 unbid suits you must first respond 1NT and on partner'e 2C inquiry bid 3C which signifies the 2 lowest suits.

F. Opponents have pre-empted at the 4-level

4NT shows the lowest 2 unbid suits.
Double suggests the 2 higher ranking unbid suits