7aaa manual - copy
Bell System Practice 508
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Bell System Practice 508-230-100 Issue 2 November 1967

 
4    Pages

Searchable  Format.

Bell System Practice 508-230-100 Issue 3 August 1964

 
4    Pages

Searchable  Format.

Bell System Practice 508-230-200 Issue 2 August 1964

 
9    Pages

Searchable  Format.