附加业务 meaning in English

additional service

Human factors - minimum man - machine interface to public network based supplementary services ; english version ets 300738 : 1997
人机因素.基于公用网络的附加业务的最低人机界面要求
In succession , h . 450 , the supplementary service for h . 323 , especially the call hold supplementary service is introduced , which can provide a more flexible ivr
接着，介绍了h . 450附加业务，它是增强ivr灵活性的基础，其中重点介绍了呼叫保持附加业务。