- 电话交换机 diànhuàjiāohuànjī telephone switchboardA machine used to connect telephone calls between users; a telephone exchange
- 程序控制自动电话交换机 chéngxùkòngzhìzìdòngdiànhuàjiāohuànjī program-controlled telephone exchangestored program control telephone exchange system; an automated telephone switching system managed by computer software
- 程控交换机 chéngkòngjiāohuànjī electronic switching systemstored program control exchange used in telecommunications