ind led ▁to ▁under ▁a ▁dozen , ▁but ▁it ▁is ▁still ▁used ▁by ▁h ob by ists , ▁manufact ur ers ▁and ▁in ▁industrial ▁applications . ▁ ▁Con ne ctor ▁pin ▁assign ments ▁The ▁ST D ▁Bus ▁has ▁a ▁card ▁edge ▁conne ctor ▁with ▁ 5 6 ▁contacts . ▁The ▁pin ▁configuration ▁is ▁as ▁follows . ▁Flow ▁is ▁relative ▁using ▁a ▁ST D ▁Bus ▁Process or ▁Card . ▁ ▁App lications ▁The ▁ST D ▁bus ▁system ▁was ▁more ▁adapt able ▁to ▁various ▁applications ▁than ▁the ▁contemporary ▁computer ▁bus es ▁of ▁the ▁mid - 1 9 8 0 s , ▁because ▁it ▁could ▁use ▁ser vo ▁control ▁cards ▁along ▁with ▁a ▁fully ▁program m able ▁computer ▁for ▁mathematical ▁operations . ▁ ▁In ▁applications ▁for ▁running ▁an ▁astronom ical ▁observ atory , ▁the ▁large ▁industrial ▁base ▁of ▁cards , ▁and ▁the ▁system ' s ▁expand ability , ▁made ▁the ▁system ▁des irable ▁for ▁use ▁in ▁a ▁phot ometry ▁lab ▁to ▁control ▁the ▁teles cope ▁as ▁well ▁as ▁do ▁the ▁data ▁logging ▁and ▁comput ations ▁required . ▁ ▁ST D - 3 2 ▁The ▁ST D - 3 2 ▁is ▁a ▁pin ▁compatible ▁ST D ▁interface ▁that ▁allows ▁the ▁co - ex istence ▁of ▁both ▁ 8 - bit ▁and ▁ 3 2 - bit ▁systems ▁on ▁a ▁single ▁bus . ▁This ▁is ▁accomplished ▁by ▁the ▁addition ▁of ▁p ins ▁between ▁the ▁normal ▁p ins ▁that ▁do ▁not ▁connect , ▁nor ▁do ▁they ▁inter f ere ▁with ▁the ▁original ▁specification . ▁This ▁allows ▁with ▁the ▁proper