FXO and FXS Parameters

Defines a descriptive name for an analog port. This can be used to easily identify the port.

The valid value is a string of up to 40 characters. By default, the value is undefined.

Note:

Determines the FXS line characteristics (AC and DC) according to USA or Europe (TBR21) standards.

Note: For the parameter to take effect, a device restart is required.

Enables the device to detect pulse (rotary) dialing from analog equipment (e.g., telephones) connected to the device's FXS port interfaces.

Note: For the parameter to take effect, a device restart is required.

Determines the FXO line characteristics (AC and DC) according to USA or TBR21 standard.

Note: For the parameter to take effect, a device restart is required.

Defines the FXO line DC termination (i.e., resistance).

Note: For the parameter to take effect, a device restart is required.

Enables limiting the FXO loop current to a maximum of 60 mA (according to the TBR21 standard).

Note: For the parameter to take effect, a device restart is required.

Enables electrical overload protection on FXO interfaces.

Note: For the parameter to take effect, a device restart is required.

Defines the number of rings before the device's FXO interface answers a call by seizing the line.

The valid range is 0 to 10. The default is 0.

When set to 0, the FXO seizes the line after one ring. When set to 1, the FXO seizes the line after two rings.

Note:

Global parameter defining the dialing mode for IP-to-Tel (FXO) calls.

You can also configure the feature per specific calls, using Tel Profiles ('Two Stage Dial' parameter). For a detailed description of the parameter and for configuring the feature in the Tel Profiles table, see Configuring Tel Profiles.

Note: If the feature is configured for a specific Tel Profile, the settings of the global parameter is ignored for calls associated with the Tel Profile.

Determines whether or not the device waits for a dial tone before dialing the phone number for IP-to-Tel (FXO) calls.

When one-stage dialing and the parameter are enabled, the device dials the phone number (to the PSTN/PBX line) only after it detects a dial tone.
If the parameter is disabled, the device immediately dials the phone number after seizing the PSTN/PBX line without 'listening' for a dial tone.

Note:

Defines the delay before the device starts dialing on the FXO line in the following scenarios:

The valid range (in milliseconds) is 0 to 20,000 (i.e., 20 seconds). The default is 1,000 (i.e., 1 second).

Defines the timeout (in seconds) for detecting the second ring after the first detected ring.

If automatic dialing is not used and Caller ID is enabled, the device seizes the line after detection of the second ring signal (allowing detection of caller ID sent between the first and the second rings). If the second ring signal is not received within this timeout, the device doesn't initiate a call to IP.

If automatic dialing is used, the device initiates a call to IP when the ringing signal is detected. The FXO line is seized only if the remote IP party answers the call. If the remote party doesn't answer the call and the second ring signal is not received within this timeout, the device releases the IP call.

The parameter is typically set to between 5 and 8. The default is 8.

Note:

Determines the number of rings before the device starts detecting Caller ID.

Defines the time interval (in seconds) after a call has ended and a new call can be accepted for IP-to-Tel (FXO) calls.

The valid range is 0 to 10. The default is 1.

Note: Occasionally, after a call ends and on-hook is applied, a delay is required before placing a new call (and performing off-hook). This is necessary to prevent incorrect hook-flash detection or other glare phenomena.

Global parameter enabling the FXO Double Answer feature, which rejects (disconnects) incoming Tel-to-IP collect calls and signals (informs) this call denial to the PSTN.

You can also configure the feature per specific calls, using Tel Profiles ('FXO Double Answer' parameter). For a detailed description of the parameter and for configuring the feature in the Tel Profiles table, see Configuring Tel Profiles.

Note: If the feature is configured for a specific Tel Profile, the settings of the global parameter is ignored for calls associated with the Tel Profile.

Defines the delay (in msec) before the device generates a SIP INVITE (call) to the IP side upon detection of a RING_START event from the Tel (FXO) side. This occurs instead of waiting for a RING_END event.

This feature is useful for telephony services that employ constant ringing (i.e., no RING_END is sent). For example, Ringdown circuit is a service that sends a constant ringing current over the line, instead of cadence-based 2 second on, 4 second off. For example, when a telephone goes off-hook, a phone at the other end instantly rings.

If a RING_END event is received before the timeout expires, the device doesn't initiate a call and ignores the detected ring. The device ignores RING_END events detected after the timeout expires.

The valid value range is 0 to 50 (msec), in steps of 100-msec. For example, a value of 50 represents 5 sec. The default value is 0 (i.e., standard ring operation - the FXO interface sends an INVITE upon receipt of the RING_END event).

Note: The parameter can be configured for a Tel Profile.

Defines the time (in msec) that the device waits before opening the RTP (voice) channel with the FXO endpoint, after receiving a 200 OK from the IP side. This delay may be useful in scenarios in which a 'click' noise is audible when the FXO interface (PBX) seizes the line. A delay in opening the voice channel eliminates this noise.

The valid range is 0 (default) to 500, where 0 means that the device opens the voice channel immediately upon the receipt of the 200 OK.