00862nam--2200301---450-99000331221020331620090916104628.0000331221USA01000331221(ALEPH)000331221USA0100033122120090916d1982----km-y0itay50------baengGB||||||||001yyIntroducing computerised telephone switchboards (PABXs)MAnchesterNational Computing Centre198292 p.ill.21 cmTelefonia621.385ITsalbcISBD990003312210203316621.385 INT19425/CBS621.38500327499BKSCIRSIAV69020090916USA011046Introducing computerised telephone switchboards (PABXs1122259UNISA