ITU-T E.300-1988 Special Uses of Circuits Normally Employed for Automatic Telephone Traffic - Telephone Network and ISDN - Operation, Numbering, Routing and Mobile Service (Study Group II) 2 pp
that special services exist which occasionally require the provision of telephone circuits for uses such as
ITU-T E.300-1988 history
1993ITU-T E.300-1993 Special Uses of Circuits Normally Employed for Automatic Telephone Traffic
1988ITU-T E.300-1988 Special Uses of Circuits Normally Employed for Automatic Telephone Traffic - Telephone Network and ISDN - Operation, Numbering, Routing and Mobile Service (Study Group II) 2 pp