Telecommunication Switching and Networks - Google Book Search
[http://books.google.co.in/books?id=btVRxi1-JLMC&pg=PA98&lpg=PA98&dq=three+stage+switching+structure++128+inlets&source=bl&ots=s0-Krg2UrJ&sig=gZKui_Ux6c5oqH1aop9S0RbMQT8&hl=en&ei=9ZwJSpiTNabe6APHsLGpCQ&sa=X&oi=book_result&ct=result&resnum=4#PPA2-IA3,M1] - - public:npranothi