PABX:Private Automatic Branch eXchange,自动用户交换机。关联词:LE、PBX
PAMA:Private Automatic Message Accounting,用户交换机自动计费。关联词:CAMA、LAMA
PBX:Private Branch eXchange,用户交换机。关联词:PABX
POTS:Plain Ordinary Telephone Service,常规电话业务
PSTN:Public Switched Telephone Network,公用交换电话网