# Limiting call attempts by automatic dialers

International regulatory approvals require you to limit attempts by an automated dialer to call a given number. Limits are placed on both the number and the frequency of the call attempts. For example, most European countries restrict the number of call attempts to a given address to 15, with a minimum interval of 5 seconds between each call attempt.

The NCC API provides functions that enable you to comply with these international regulatory requirements. These functions can be accessed by any application using the ADI implementation of NCC.

During installation, repeat dial attempt functionality is disabled by default. Follow this procedure to enable this functionality:

Step | Action
1 | Rename rda.dlx (located in the \bin directory of the installation) to rda.dll. If you are running under UNIX, rename librda.sx to librda.so.
2 | Create an rda.cfg file specifying the rules for repeat dialing, and place this file in the CTA_DPATH.

## Creating rda.cfg

rda.cfg consists of one line with three positive integers, each separated by a space. The first integer specifies the maximum number of calls that can be made in a series to a given address. The second integer specifies the minimum interval, in seconds, between calls to the same address. The third integer specifies the minimum interval, in minutes, between series' of calls to the same address.

For example, an rda.cfg with the following line:

3 10 1

permits a maximum of 3 calls in each series. Each of these calls must be separated by at least 10 seconds. If an application attempts to place a call to an address within 10 seconds of the most recent call, NCCERR_ADDRESS_BLOCKED is returned. After 3 successful calls, 1 minute must pass before a call to the same address is allowed. If the value of the third parameter is 0, no further calls can be placed to the given address until the log is manually reset.

Note: The call attempt series parameters apply to wrong numbers and unsuccessful calls. The maximum interval between call attempts is 12 minutes.

## Repeat dial regulations

The following table lists repeat dial regulations by country:

Country | Maximum number of call attempts | Minimum interval (seconds) between call attempts | Minimum interval (minutes) to wait for a new series
--- | --- | --- | ---
European countries | 15 | 5 | -
Australia | 31 | - | 30
Bulgaria | 12 | 2 | 60
Czech Republic | 12 | 5 | -
Israel | 15 | 30 | -
Japan | 3 in 3 minutes, or 15 | - 5 | 3 -
Korea | 3 | 30 | -
Malaysia | 2 | 120 | -
New Zealand | 5 | 60 | -
Singapore | 10 | 60 | -
Slovakia | 12 | 60 | -
South Africa | - | 60 | -
Taiwan | 2 | 60 | -

In Australia, for equipment with a service tone detector, a maximum of 10 calls is allowed. In New Zealand, not more than five call attempts to the same number within a 60-minute period, with a minimum of 60 seconds between attempts, is allowed. A total of 10 call attempts to the same number is allowed.