manual multiple type switchboard人工复式交换台

non multiple teletypewrite switchboard非复式电传交换台

manualcleaning separator multiple type switchboard人工复式交换台

bridging multiple switchboard并联复式交换机

extensible multiple switchboard可扩充的复式交换机

multiple common battery switchboard复接式交换机

non-multiple switchboard单式交换机

non multiple switchboard无复接交换台

series multiple switchboard串联复式交换机