RELAYS IX THE DELL SYSTEM 



27 



Till-: (\)iNTiN(. Re;i.ay 

 The rt'l.iN- dosiKni'tl for a coimliiij; rt-lay is shown in l'"ij;. 18 and 

 has tho (luahtics of spi'itl and rrhahility that arc reciuired. It is 

 C(iiii(>p»'<l witli .1 Hk'i' arin.iluri', on a pivot suspcMision, tliat (i|)crati's 



Fig. 18 — Coiintiiig relay 



through a small air gap. The contacts arc mounted on rit;id springs 

 that cannot be adjusted readily, but which maintain a given adjust- 

 ment, without change, for a long time. This rela>', like the stepping 



ii;. 19 Call indicator circuit 



relay, is unique, in that, it is not used for any other purpose in the 

 telephone system, and in addition all attempts to design a punched 

 type relay that is a satisfactory substitute ha\e, so far, been un- 

 successful. 



Cert.ain M.vrginal and Polarized Relays 



Another interesting and unusual use of relays is the arrangement 



at the terminating end of a call indicator trunk from a full mechanical 



to a manual office. This arrangement consists of three relays in 



series in the manual office, as shown in Fig. HI. One of them is a 



