606 THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1953 



Fig. 10 — Terminal at left exposed to H2S for 14 hours and then 30 months at 

 85°F 90%RH. The connections did not develop resistance variation in excess of 

 the 0.002 ohm limit. Corresponding new terminal is shown at right. 



which meet the 3,000-gram strip-ofif requirement appear satisfactory on 

 the other tests, the strip-off test used on a sampling basis has been stand- 

 ardized as the shop control of the wrapping tool and indirectly of the 

 quaUty of the connections themselves. 



FIELD TRIALS 



A number of equipment units using these connections is currently on 

 field trial. At Tonawanda, N. Y., one trunk unit using wire spring relays 

 of an early design and 300 solderless wrapped connections has been in 

 service successfully since 1951. At Elmhurst, L. I., a sender frame com- 

 prising five senders with about 7,500 connections has been in use about 

 a year and a half with no troubles reported to date. At Boston, Mass., 

 an outgoing sender frame for the No. 4 crossbar office comprising three 



