This feature enhances system reliability by providing the ability to physically and electrically connect the two DS1 ports (T1/E1) in the event of a loss of electrical power to the SBC 1000. It also allows you to maintain connectivity between the PSTN or other T1/E1 connection and the PBX or other gateway on the enterprise side while the SBC 1000 is being configured. You can physically install the SBC 1000, select the Passthrough mode, and continue configuring the SBC 1000 with no interruption to network/phone services. When the SBC 1000 is ready to be placed into service, simply "flip the switch", (i.e., select either Online or Powerdown Passthrough mode) and the SBC 1000 will be online and fully functioning as a gateway between the external (i.e., ISDN side) and the internal side of the connection.

(info) This feature is available on the SBC 1000 only.

For DS1 only: the Relay Config option appears only when two interfaces are on the same licensed T1/E1 card.

Configuring the Relay State

To configure the relay state:

  1. In the WebUI, click the Settings tab.

  2. In the left navigation pane, go to Node Interfaces > Relay Config.

    Relay Configuration

  3. Select the appropriate option in the Relay Config State field.

DS1 Relay Configuration - Field Definitions

DS1 Relay Config State

Specifies the Powerdown Telephony Passthrough mode for DS1 ports.

Online Mode Operation
In the Online Mode the SBC 1000 operates as a gateway between the two DS1 (T1/E1) ports, if power is lost, then connectivity between the two ports is also lost.

Passthrough Mode Operation
In the Passthrough Mode the two DS1 (T1/E1) ports are physically and electrically connected by a relay.

Powerdown Passthrough Mode Operation
In the Powerdown Passthrough Mode, the two DS1 (T1/E1) ports operate normally, using the SBC 1000 as a gateway unless the SBC 1000 loses power. If the SBC 1000 loses power the DS1 (T1/E1) ports are physically and electrically connected by a relay.

Analog Relay Configuration - Field Definitions

This panel is not visible when no FXS/FXO cards with relays are installed.
The Analog Relay Configuration panel is only visible when the following conditions are true:

  • FXS cards with relays are installed in the lower slots (1,3, and 5).
  • FXO cards are installed in the upper slots directly above the corresponding FXS cards.

Relay Config State

Specifies the Powerdown Telephony Passthrough mode for FAX/FXO ports.

Online Operation
In the online mode, the analog (FXS/FXO) ports are controlled and routed by the SBC.

If the SBC is powered down, the FXS and FXO ports are physically and electrically connected in the same manner as they are in the passthrough mode.

Passthrough Operation
In the passthrough mode, the FXO and FXS ports are physically connected via relays. In this mode, there is a 1:1 correspondence between FXS and FXO ports. FXS port 1:1 is physically/electrically connected directly to FXO port 2:1, FXS port 1:2 connects to FXO port 2:2, etc.

Relay Configuration State