A SIM server provides access to the SIMs, a SIM librarian catalogs {HEAD ~ the SIMs}, and a SIM accounting system tracks {TAIL ~ and/bills} for SIM usage 
A SIM server provides access to the SIMs , a SIM librarian catalogs { HEAD ~ the SIMs } , and a SIM accounting system tracks { TAIL ~ and / bills } for SIM usage
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH