Message formats and protocols for serial data interfaces in alarm transmission systems-Part 9:PTT interfaces for dedicated communications channels using ITU-T recommendation V.23 signalling
Message formats and protocols for serial data interfaces in alarm transmission systems-Part 8:Serial protocol for use by digital communication systems using ITU-T recommendation V.23 signalling at interfaces with the PSTN
Message formats and protocols for serial data interfaces in alarm transmission systems-Part 7:Alarm system interfaces for plug-inalarm system transceivers