首页 / 官方藏书 / Cyclopedia of Telephony and Telegraphy, Vol. 2 / A General Reference Work on Telephony, etc. etc. / CHAPTER XXVI THE COMMON-BATTERY MULTIPLE SWITCHBOARD

CHAPTER XXVI THE COMMON-BATTERY MULTIPLE SWITCHBOARD

Cyclopedia of Telephony and Telegraphy, Vol. 2 / A General Reference Work on Telephony, etc. etc. · American School of Correspondence · 第 4 / 233 章