TELEPHONE EQUIPMENT TOR LONG CABLE CIRCUITS 127 



apparatus as at the primary board. The jacks to be located 

 at this position are to include those designated as "secondary 

 line jacks," "drop jacks" and "listening jacks," in Fig. 12. 



3. Secondary telegraph line positions for testing and "patching" 

 the telegraph line circuits. This position is to be used solely 

 for interchanging telegraph lines and telegraph equipment, in 

 cases of temporary changes in assignment and is not to be 

 equipped with the line testing apparatus. This position will 

 permit changes to be made in the telegraph assignments without 

 interfering with the telephone circuits. The jacks to be located 

 at this position are to include those designated in Fig. 12 as 

 "telegraph line jacks" and "telegraph drop jacks." 



A further and more extensive improvement in test board design is 

 anticipated as a result of development work whereby it will be pos- 

 sible to employ panel mounted keyshelf equipment units, jacks and 

 testing apparatus, which in the standard board are now housed in a 



PATCHI 



CORDS 

 ANCL PLUGS 



Fig. 14 — Typical Assembly of Floor-Mounted Test Board — One Position 



large wooden section. This will have the advantage of uniformity 

 with the other toll equipment, as well as requiring less space. It will 

 also permit flexibility in the use and installation of the various com- 

 binations of keyshelf equipment, jack equipment and other testing 



