
Public Switched Telephone Network (PSTN); Messages and formats for push-button dialling [CEPT Recommendation T/CS 28-01 E (1980)]
STANDARD published on 15.9.1995
    
        Designation standards: ETSI ETR 203-ed.1
                
                
                
               
                Publication date standards:  15.9.1995
        The number of pages: 7
Approximate weight : 21 g (0.05 lbs)
        Country:          European technical standard
        Category: Technical standards ETSI