This sets how long the outgoing line signal stays in its released/break state before reverting to the original pattern that was in effect before this signal was asserted, with 0 meaning no break period at all. This governs how quickly the gateway can re-assert or repeat an outbound signal, since a break period that is too short might not give the far end enough time to detect the release before the next signal appears. With this set to 0, the gateway would assert a signal and then jump immediately back to it, or the next one, without any intervening idle-pattern period, which is appropriate only for signals that do not require an explicit release gap.