A method for providing alarm notification and two-way voice communication for a hybrid data/voice system, said method comprising: an alarm system including a remote communication device detecting an alarm event of a premises under surveillance when the alarm system is armed and a disarm code is not entered on a security system keypad within a predetermined time; sending an alarm notification from the remote communication device to a central station via a digital data service implemented by a network using a data transmission method; associating the alarm notification with a central station telephone number operable with a voice transmission method, said step of associating comprising the steps of: the central station selecting a line number from a group or block of line numbers, each having a corresponding central station telephone number; the central station verifying the availability of the selected line number; and the central station sending, using the data transmission method, an acknowledgement message of the alarm notification to the remote communication device, if the line number is available, the acknowledgement message containing the central station telephone number corresponding to the line number selected by the central station; and initiating a two-way voice communication between said remote communication device and the central station using a voice transmission method. an alarm system including a remote communication device detecting an alarm event of a premises under surveillance when the alarm system is armed and a disarm code is not entered on a security system keypad within a predetermined time; sending an alarm notification from the remote communication device to a central station via a digital data service implemented by a network using a data transmission method; associating the alarm notification with a central station telephone number operable with a voice transmission method, said step of associating comprising the steps of: the central station selecting a line number from a group or block of line numbers, each having a corresponding central station telephone number; the central station verifying the availability of the selected line number; and the central station sending, using the data transmission method, an acknowledgement message of the alarm notification to the remote communication device, if the line number is available, the acknowledgement message containing the central station telephone number corresponding to the line number selected by the central station; and initiating a two-way voice communication between said remote communication device and the central station using a voice transmission method. the central station selecting a line number from a group or block of line numbers, each having a corresponding central station telephone number; the central station verifying the availability of the selected line number; and the central station sending, using the data transmission method, an acknowledgement message of the alarm notification to the remote communication device, if the line number is available, the acknowledgement message containing the central station telephone number corresponding to the line number selected by the central station; and initiating a two-way voice communication between said remote communication device and the central station using a voice transmission method.