Do you mean T+1? All trades, payed for, are T+3. And proceeds are offset. T+1 is where you can buy but close the trade by close of trade the following day without having funds, but, if the trade loses money you have to have the loss available at T+3. It's like buying 'on tick', but they do weigh it up against your holdings how much you're good for.
The following is for T+3:
For stocks, the settlement period is three days (T+3) after the transaction. This means that the buyer must transfer cash to the seller, and the seller must transfer ownership of the stock to the buyer within three days after the trade was made.
