# ISDN Options

Integrated Services Digital Network (ISDN) is an international communications standard for sending voice, video, and data over digital telephone lines.

After you configure the basic properties for the Basic Rate Interface (BRI) (see WAN Interface Configuration), then edit the following options to configure your device for ISDN functionality:

Hold Time: Specifies how much time can pass before the device considers the interface connection to be up or down. The range is 0 to 65534 (milliseconds). The default value for up/down time is 0.

Up: Enter a value in milliseconds to configure the hold-time period. If an interface goes from up to down, it is not advertised to the rest of the security device as being down until it has remained down for the specified Up period.

Down: Enter a value in milliseconds to configure the hold-time period. If an interface goes from down to up, it is not advertised to the rest of the security device as being up until it has remained up for the specified Down period.

BRI Options

Flag in Idle Cycles: Select ones (0xFF) or flags (0x7E) to configure the value the BRI transmits during its idle cycles. The device needs to transmit something during idle-cycles in order to keep the line up. The default is ones (0xFF).

Loopback Mode: Select local or remote. Loopback mode is disabled by default. If you select local loopback mode the transmitted data is looped back to receiver through the S-interface. If you select remote line loopback mode, the received data is looped back to the S-interface. The D-channel information received from the line card is output transparently to the S-interface.

ISDN Options

Current Switch Type (read only): Identifies the ISDN switch to which your device is connected. The first time your device boots up, this option displays not configured.

Switch Type After Reboot: Select the ISDN switch with the help of your Internet Service Provider (ISP). Do not change the switch type during operation. The updated switch type will take into effect after the device reboots.

SPID1 and SPID2: If you are using an ISP that requires a Service Profile Identifier (SPID), your device cannot place or receive calls until it sends a valid, assigned SPID to the ISP when it accesses the ISDN switch to initialize the connection.

Enter a number that specifies the service available to you on the ISDN switch and defines the feature set ordered when you provisioned for the ISDN service. A SPID number is usually a seven-digit telephone number with some optional numbers. However, different ISPs may use different numbering schemes.

Note: Currently, only the DMS-100 and ni1 ISDN switch types require SPIDs. For the DMS-100 switch type, two SPIDs are assigned, one for each B-channel. Do not specify the SPIDs if you selected the AT&T 5ESS ISDN switch type. In addition, SPIDs are important at the local access ISDN interface only. Remote routers do not receive the SPID.

TEI Negotiation: Terminal Endpoint Identifier (TEI) identifies each terminal that connects to the ISDN switch. It's always dynamically assigned by the switch. Select Power Up if you want the switch to assign TEI once the device boots up. Select First Call if you want the device to activate the TEI negotiation when the first call is made. Both selections conform to different standards, ANSI & ETSI. The default is First Call.

TEI negotiation is useful for switches that may deactivate Layer 1 or 2 when there are no active calls. Typically, this setting is used for ISDN service offerings in Europe and connections to DMS-100 ISDN switches that are designed to initiate TEI negotiation.

Calling Number: The device supplies the ISDN with a billing number for outgoing calls. The device dials the number, and the switch selects the route. Some networks offer better pricing on calls where the number is presented. When configured, this information is included in the outgoing call-setup message.

T310 Value: Enter the duration of the T310 timeout value in seconds. The range is 5 to 100, and the default is 10. If an ALERT, a CONNECT, a DISC, or PROGRESS message is not received after a CALL PROC message, a DISC message is sent to the network side for the duration of the T310 timeout value.

Send Complete: Some countries require you to check this option. In certain geographic locations, such as Hong Kong and Taiwan, ISDN switches require that the Send Complete information be included in the outgoing call-setup message to indicate that the entire number is included. This information element is generally not required in other locations. The default is not set.