A protocol entity forming part of the application layer. It provides a generalized facility for exchanging electronic message between systems. It is also known as X.400.; 一种构成应用层中一部分的协议实体。 该协议实体在系统之间提供交换电子报文的通用化设施。报文处理服务层也称为X.400。 message handling system (mhs): 信息处理系统mhs message handling systems: 消息处理系统mhs message-handling system: 信息处理系统message handling service: 消息处理服务message handling: 消息处理; 信息处理; 讯息处理下载手机词典可随时随地查词查翻译