当用户交换机卡卡在甲板上，我们需要存储数据的变量。

When a user switches from card to card in a deck, we need to store data in variables.

这就要求用新型的电路交换网关，它们具有局域网接口和与公用网和用户交换机电话中继线连接的特点。

This requires new kinds of circuit-switching gateways that feature LAN interfaces and telephony trunk connections to public networks and PBXs.

当话音电话成了另一种局域网应用时，PC机就成了电话，具有呼叫控制服务器的局域网成了用户交换机。

When voice telephony is just another kind of LAN application, the PC becomes the telephone, and the LAN-together with its call-control server becomes the PBX.