common battery telephone switch board

例句：

1. 1.The common telephone exchange is located in the center of the city.
   公用电话交换台位于市中心。
2. 2. The public telephone exchange provides free calls to certain areas.
   公共电话交换台为某些地区提供免费通话服务。
3. 3.The common telephone exchange has been upgraded to support higher data rates.
   公用电话交换台已升级，以支持更高的数据传输速率。