The Interop submenu normally does not have to be adjusted. This is only necessary if, for example, malfunctions occur when transmitting H.323 calls.
Not all ISDN implementations are prepared to receive certain standard-compliant information elements (referred to as IEs). Such IEs can be created, for example, when linking up different PABXs or transmitting H.323 calls to an ISDN interface and vice-versa.
If malfunctions are caused by the transmission of certain IEs, the gateways can be made to remove such IEs from the transmitted messages.
- Automatic Keypad
- This options enables Automatic Keypad sending. This means that if the first dialed digit to be sent on this interface is either '*' or '#' the digits are not sent as called party number, but as Keypad information instead. This is used on some ISDN networks for non call related supplementary services (e.g. *21*No# to set call forwarding).
- Suppress HLC
- The HLC (Higher Layer Compatibility) information element is used to provide end to end information about the application (e.g. Telephony) of the call. Very rarely ISDN implementations do no support it and thus reject calls. With this checkmark the sending of the HLC can be suppressed. Desciprition of HLC Protocol Features
- Suppress FTY
- The FTY (Facility) information element is used for supplementary services. This option suppresses the sending of FTY to avoid problems with incompatibilities of the facilities. No Supplementary Services are possible in this case.
- Suppress Subaddress
- No subaddress information elements are transmitted.
- Suppress Connected Num.
- No connected number information elements are sent to the ISDN (they are still received though).
- No Restart
- The Restart procedure is used by the device after establishment of the link layer to make sure no call exists on any channel. This is useful because some PBXs do no clear all calls if the link layer is disconnected. With this option this restart procedure is disabled.
- Passive Layer2
- Normally the device tries to establish the link layer on point to point interfaces as soon as the physical layer is established. This behaviour is especially incompatible to some ISDN conformance test equipment even if it conforms to standard. This option turns this off.
- No Overlap Receive
- Normally, single digit dialing (overlapped sending) is not used to call terminals (that is, devices in TE mode) on point-to-multipoint connections. Under certain circumstances however, it is possible for gateways to be connected to a PABX system in precisely this mode and then also support incoming single digit dialing (overlapped receive). In this case, an incoming SETUP message is answered, as required in the standard, with a SETUP_ACK message. Some PABXs, however, do not expect this sort of message from terminal equipment and terminate the call at this point. In such a case, the No overlap receive setting prevents the gateway from answering the incoming SETUP message with a SETUP_ACK.
- No Disc
- No DISC message is transmitted. REL is transmitted instead. If DISC is received a RELEASE response is sent right away.
- No Disc for Call Reject
- Call Rejection is done with REL message instead of DISC.
- Annex N
- Signals the sending of inband information during call establishment according to ETS 300 102-1 Annex n (only in TE mode).
- Automatic Progress
- Send PROGRESS message automatically after a CALL_PROC message. Some networks have short timeouts (4-6s) for incoming calls after a CALL_PROC (which indicates that the called number exists and is complete) is sent. This can create problems if the incoming call is forwarded to a mobile number or any other destination which takes some time to respond. The PROGRESS message stops this timer.
- Network CLI only
- Any CLI received on incoming calls, which is not marked as 'Network provided' or 'User provided and screened' is igored. This may be needed for applications which do not want to trust a CLI provided by the CLIP no screening feature.
- Here, you can set a value in decibel (dB) between -32dB and +32dB to define the output volume to the BRI interface.
- CR Length
- Length of call reference value in bytes. Normally the length of the Call reference is defined by the standard. Especially in the QSIG environment deviations from the standard are found, so it can be adjusted manually.
- CHI Type
- Coding of the Channel Information Element is different for Basic Rate (BRI) and Primary rate (PRI) interfaces, but for QSIG the PRI coding is defined for BRI interfaces as well. Some QSIG implementation use BRI coding of the Channel Information Element on a BRI interface. With this option the coding can be adjusted manually.