Recommendation U.40 (11/1988): Reactions by automatic terminals connected to the telex network in the event of ineffective call attempts or signalling incidents
['Recommendation F.60', 'Recommendation U.40 (11/1988): Reactions by automatic terminals connected to the telex network in the event of ineffective call attempts or signalling incidents', '1988-11-25', 'ITU Telecommunication Standardization Sector']