ISDN D-Channel

The ISDN D-Channel carries control and signaling information needed to connect or disconnect calls and to negotiate special calling parameters in an ISDN network. The ISDN D-Channel object configures a D-Channel along with a set of D-Channel attributes onto a specific DS-1/Span and DS-0/Channel. To create the D-Channel object, right click on the ISDN D-Channels object and select ISDN D-Channel. See below for more information on configuring the ISDN D-Channel object.

Web GUI Page

Dialogic > IMG 2020 > Signaling > ISDN > New ISDN D Channel (T1 D-Channel object pane displayed below)

Open

Maximum Objects

T1 - Up to 84 D-Channels, one for each T1 DS-1. 
E1 – Up to 63 D-Channels, one for each E1 DS-1.

Related Topics and Dependencies

ISDN - Signaling
Configure ISDN

Field Descriptions

Primary Span

This field is a drop down menu that contains all the spans configured. Select from the menu which span the D-Channel will get configured on.

Primary Channel

Select from drop down menu which Channel the D-Channel will get configured on.

Secondary Span (T1 Only)

Select from drop down menu which Channel the D-Channel will get configured on. Supported in T1 only.

Secondary Channel (NFAS Only)

If configuring a secondary D-Channel select which channel the secondary D-Channel will get configured on. (Default is Not Used)

NFAS Supported

Select Yes from drop down if NFAS is being configured. Select No if configuring FAS. If IMG 2020 is configured for the E1 protocol, the NFAS Supported field will be shaded green and it cannot be modified.

Base Variant

Select from the drop down menu which Base Variant will be used. Verify that the correct side is being configured. (Either User or Network). The default is National-ISDN 2 Network Side.

Note: Depending on which Base Variant is being configured will dictate the number of B-Channels that can be configured. The table below lists the variants supported and number of B-Channels that can get configured for each. The table below does not include the span that the D-Channel is configured on.

B Channel Selection

Select from a drop down menu which method to use to access a B-Channel when a call comes into the IMG 2020. The Default value is Linear Clockwise.

Linear Clockwise (default) - The search for an idle B-Channel begins at the first B-Channel in the D-Channel FAS/NFAS Group and proceeds in order towards the last B-Channel.

Linear Counter Clockwise - The search for an idle B-Channel begins at the last B-Channel in the D-Channel FAS/NFAS Group and proceeds in order towards the first B-Channel.

Circular Clockwise - Starts at the first channel in the channel group and routes down. If a prior channel becomes available this channel is used before selecting the next channel from the end of the list.

Circular Counter Clockwise - Starts at the last channel in the channel group and routes up. If a prior channel becomes available this channel is used before selecting the next channel from the end of the list.

HDLC Bit Polarity

Select from drop down menu whether Bit Polarity is Normal or Inverted.

Network Side Layer 2 Override

Select from drop down menu whether the D-Channel being configured is to be configured on the Network or User Side. If the opposite entity connected to the D-Channel on the IMG 2020 is set as the Network side, the D-Channel should be set as the User side. If the opposite entity connected to the D-Channel on the IMG 2020 is set as the User side, the D-Channel should be configured as the Network side.

Location

The value populated in the Location parameter in the Cause IE when a call is released. Location values include:

Monitoring Fields

Primary D Channel Status

Monitors and displays the status of the Primary D-Channel.

Secondary D Channel Status

Monitors and displays the status of the secondary D-Channel.

Buttons

In Service - Clicking on the In Service button brings the configured D-Channel In Service. If both a Primary and Secondary D-Channel are configured,  both the Primary and Secondary D-Channel will be brought back into service. Note that a switchover may have occurred when the Primary and secondary D-Channels were taken Out Of Service.

Out Of Service - Clicking on the Out of Service button takes the D-Channel configured Out Of Service. If both a Primary and Secondary D-Channel are configured,  both the Primary and Secondary D-Channel will be taken Out Of Service.

Switch Over - By clicking on the Switch Over button, The Primary D-Channel which was previously in the active state will switch and go into the standby state. The Secondary D-Channel which was previously in the standby state will switch and go into the active state.