>> FbTransactionBehavior t_behaviour;
>> FbTransactionOptions t_options;
>>
>> t_behaviour = FbTransactionBehavior.NoWait;
>> t_options.TransactionBehavior = t_behaviour;
>>
>> FbConnection conn = new FbConnection();
>> conn.BeginTransaction(t_options);
>>

> should that be t_behaviour = FbTransactionBehavior.Wait?

Depends on the transaction it should be applied to, A or B :-)

Seriously, I thought that "Wait" is default and that this default
leads to a behaviour the OP wanted to change. It is not clear for me,
what exactly is meant by "deadlock".

Personally, if I had this problem, I'd probably want to have "NoWait",
raise an exception, catch and deal with it.

have fun!
André