公用电话交换网public switching telephone network 用户交换机private branch exchange 自动用户交换机private automatic exchange 综合业务数字网Integrated Service Digital Network 网关Gateway 非对称数字用户环路Asymmetric Digital Subscriber Loop 保留hold 转接transfer DTMF:复频信号Dual Tone Multi-Frequency
PULSE:脉冲信号
Ring:响铃信号
拨号音:Dial Tone
回铃音:Ring Back Tone
忙线音:Busy Tone
空号音:Error Tone
转接取回retrieve 内线呼叫internal call 外线呼叫external call 响铃代接call pick up 指定代接directly pick up 勿打扰do not disturb 会议通话conference 忙线跟随busy forward 无应答跟随no answer forward 全部跟随all call forward 忙线驻留busy camp on 呼叫等待call waiting 简码速拨speed dial 呼叫值机台operator call 分机寻线群hunting group |