special purpose telephone

例句：

1. 1.This special purpose telephone is designed for emergency communication.
   这款专用电话是为紧急通讯设计的。
2. 2. The company's new special purpose telephone system will improve customer service.
   公司的新专用电话系统将提高客户服务。
3. 3.The special purpose telephone was used to connect the two remote locations.
   这个专用电话被用来连接两个偏远的位置。