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Configuring 2W-FXS Port Parameters for VComp Bundles (CTP Menu)

This topic describes how to configure port parameters for 2W-FXS interfaces.

Before you begin:

  • Disable the bundle before you modify the bundle options.

To configure port parameters for 2W-FXS interfaces using the CTP Menu:

  1. From the Main Menu, select 1) Bundle Operations.
  2. Select 4) VCOMP.
  3. Select a bundle from the list.

    If you select an active bundle, you are prompted to disable the bundle before configuring it.

  4. Select 3) Port Config.
  5. Follow the onscreen instructions, and configure the options as described in Table 1.
Table 1: VComp Bundle 2W-FXS Port Parameter Settings in the CTP Menu
Field Function Your Action

Voice port Tx gain

Specifies the gain in the direction from the analog interface toward the IP network.

Enter a number from -15.db through 10.4 db.

Voice port Rx gain

Specifies the gain in the direction from the IP network to the analog interface.

Enter a number from -15.db through 10.4 db.


Specifies the type of analog signaling used.

Select one:

  • ground start—Typically used between a central office (CO) and a PBX to prevent glare. Glare occurs when the FXS device establishes a call and the FXO device attempts to make a call before the ring is detected.

  • loop start—Typically used for residential phones.


Enables or disables private line automatic ringdown (PLAR) signaling. PLAR allows you to connect two 2W-FXS interfaces.

You must set signaling to loop start before you enable PLAR.

For PLAR to work, both ends of the bundle must have PLAR enabled.

With PLAR, two handsets are directly connected so that when someone picks up a handset, the handset at the remote end starts to ring. There is no call routing (dialing) involved.

To hear ringback, the audible tone in the handset indicating that the far end is ringing, you must enable tone detection for the bundle.

Select one:

  • Enabled

  • Disabled