Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA644577A
Inventor
Boehm Albert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
American District Telegraph Co
Original Assignee
American District Telegraph Co
Publication date
Application grantedgrantedCritical
Publication of CA644577ApublicationCriticalpatent/CA644577A/en