NON-BLOCKING SWITCHING SYSTEMS 



409 



0OQQO9OOOOC> 



N=36 



4 OTHER 



INPUT 

 SWITCHES 



n = 6 



V P 



9 OTHER 



INTERMEDIARY 



SWITCHES 



QOppOOpOOOO 



A 

 I 



4 OTHER 

 OUTPUT 

 SWITCHES 



N=36 



k— 6~>H 



STAGE (a) STAGE (b) STAGE (c) 



NUMBER OF CROSSPOINTS = 6N^/^-3N (1188 CROSSPOINTS WHEN N =36) 



Fig. 2 — Three-stage switching array. 



nVE-STAGE SWITCHING ARRAY 



A five-stage switching array is illustrated in Fig. 4. The analysis of 

 this array can be made in the following manner. Each input and output 

 switch is assumed to have n = N^^^ inputs or outputs, respectively. 

 Connection between a given input switch and a given output switch 



SWITCHES 



n INPUTS 

 QN A PARTICULAR 

 INPUT SWITCH 

 A — 



m OUTPUTS 



ON A PARTICULAR 



OUTPUT SWITCH 



-D 



•-E 



-F 



G 



— H 



SWITCHES REQUIRED 



-i) + (nn-i)+i=n + m-i 



WHEN n = m, AB0VE=2n-l 



Fig. 3 — Principle involved. 



