Talk:Speaking tube
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More detail about types of tube and dates would be helpful. Patents? There are probably standards referring to the design and layout. Fenton Robb 00:02, 20 October 2005 (UTC)
More detail about types of tube and dates would be helpful. Patents? There are probably standards referring to the design and layout. Fenton Robb 00:02, 20 October 2005 (UTC)