瑞星卡卡安全论坛

请高手帮忙翻译下面这个句子，不胜感激！
Unless default shall be made in the redemption of this debenture upon such presentation, interest on this debenture shall cease from and after the date of redemption so designated.

其中的default希望能重点解释下。

[用户系统信息]Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; InfoPath.1)

看不太懂哈