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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.

Byte | Field Description | Value and Indication
--- | --- | ---
0 | Frame Character | 0xFF
1 | Length (MSB, LSB) | 0x0011
2
3 | Message Type (MSB, LSB) | 0x00CF (PPL Timer Configure)
4
5 | Reserved | 0x00
6 | Sequence Number | 0xSN
7 | Logical Node ID | 0xFF
8 | AIB Address Method | 0x00 (Single Entity)
9 | Number of Address Elements | 0x01
10 | Address Type | 0x09 (SS7 Link)
11 | Data Length | 0x02
12 | Data[0] Stack ID | 0x01
13 | Data[1] Link ID | 0x01
14 | PPL Component ID (MSB, LSB) | 0x002E (MTP3_LSAC)
15
16 | PPL Timer Type | 0x01 (Generic Protocol Timer)
17 | PPL Timer ID | 0x02 (MTP3_ANSI_T17)
18 | PPL Timer Value (MSB, LSB) | 0x00C8 (2 s)
19
20 | Checksum | 0xCS

See Programmable Protocol Language.
See Atomic Function.
Message Transfer Part level 3 - network level
American National Standards Institute. ANSI administers and coordinates the U.S. voluntary standardization and conformity assessment system for the
telecommunications industry. More details on these standards may be
viewed at www.ansi.org.
A digital communications link - voice, data, and video at a 2.048 Mbps rate; 30B/2D or 31B/1D (ISDN); non-North American version of T1.
A group of data bits in a specific format, with a flag at each end to indicate the beginning and the end of the frame.
Most Significant Bit
Least Significant Bit
See Address Information Block.
See Signaling System Number Seven.
A programmable software component that uses PPL state machines that can be modified with the PPL Tool.