Acceptance and Transmission of the Dialed Digits on SPA100 Series Analog Telephone Adapters

Objectives

The objective of this document is to explain how the dialed digits are accepted and transmitted on SPA122 device. When a user dials a series of digits, each sequence in the dial plan is tested as a possible match. As more digits are entered by the user, the set of candidates diminishes until only one or none are valid. When a terminating event occurs, the ATA either accepts the user-dialed sequence and initiates a call, or rejects the sequence as invalid. The user hears the reorder (fast busy) tone if the dialed sequence is invalid.

Applicable Devices

• SPA100 Series

The following explains how terminated events are processed.

Step 1. If the dialed digits do not match any sequence in the dial plan, the number is rejected.

Step 2. If the dialed digits match exactly one sequence in the dial plan, one of the following will occur :

• If the sequence is allowed by the dial plan, the number is accepted and is transmitted according to the dial plan.

• If the sequence is blocked by the dial plan, the number is rejected.

Step 3. When a timeout occurs, the number is rejected if the dialed digits are not matched to a digit sequence in the dial plan within the time specified by the applicable interdigit timer.

• The Interdigit Long Timer applies when the dialed digits do not match any digit sequence in the dial plan.

• The Interdigit Short Timer applies when the dialed digits match one or more candidate sequences in the dial plan.

Step 4. When the user presses the number key :

• If the sequence is complete and is allowed by the dial plan, the number is accepted and is transmitted according to the dial plan.

• If the sequence is incomplete or is blocked by the dial plan, the number is rejected.