The network (air) interface between a Mobile End System (M-ES) and the Cellular Digital Packet Data (CDPD)-based wireless packet data service provider network.

• 移动终端系统(M-ES)和基于蜂窝数字分组数据（CDPD)之间的网络（空中）接口，基于无线分组数据业务提供商网络。