PPL Timers

There are two types of timers available to a protocol state machine:

• Generic Protocol Timers

• Protocol-specific Timers

Generic PPL Timers

Each component has access to a list of 100 timer values that are enabled in a protocol using AFs 46, 47, and 48. Up to three timers can be enabled at any one time. Each component using timers has a table that contains the value of specific timers. Argument 2 of the Generic PPL Timer AFs is an index into the component’s timer table where the value for the required timer is located.

Example

The figure below shows the use of a timer AF in the MTP3_LSAC state machine. AF 46 initiates one of the PPL timers (in this case, Timer 2, as defined by Argument 1 of the AF). Argument 2 is the index into the component’s timer table. In this case, Argument 2 indicates Index 2 in the timer table, which is the MTP3_ANSI_T17 timer with a default value of 1s.

See the API Reference for the default values of each component’s Generic PPL Timers.

Figure 1-10 Generic Protocol Timers

Protocol-Specific Timers

The E1 component uses various timers when transmitting and receiving signaling tones or dial pulses. They are as follows:

• R2 Signaling

• DTMF Signaling

• MFR1 Signaling

• Dial Pulse

The default timer values are documented in the PPL Timer Configure message, which is used to modify any of the timer values. See the "API Reference" for more information.

Modifying Protocol Timers

You can modify all of the timers and values in the PPL Timer tables using the PPL Timer Configure message. This allows the timer values to be modified without modifying the component state machine. To modify a components Generic Protocol Timer list, indicate a Timer Type of Generic Protocol Timer (0x01), the Timer ID (index into the components timer table), and the new Timer Value. To modify an E1-specific Signaling Timer, indicate the Timer Type, Timer ID (see message), and new Timer Value.

Example API format

The following example shows how to modify the MTP3_ANSI_T17 timer from one second (default) to two seconds.