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PRI Line Troubleshooting Checklist

1. Check the line protocol

Check that the protocol for your ISDN line is the same as that  which you have selected for the Diva Media Board.

In Europe, check that the line you are connecting to really is a EuroISDN Primary Rate ISDN line.  In the UK, for instance, BT lines called 'ISDN 30' can be either EuroISDN (also called 'ETSI') or the local protocol 'DASS2'.  The latter is not compatible with EuroISDN and therefore the Diva PRI will not work with 'DASS2'.

2. Cabling

Length: If the Dialogic-supplied cable is not long enough, be sure to use a single shielded cable of a similar high-grade specification to the cable supplied with the Diva PRI.  More information on cabling.

Check RJ-45 socket:  If your Primary Rate line is terminated on an RJ-45 socket, check that the presentation is I.431.  The cable supplied with the Diva PRI is 'straight' and will only work if the pin-out of the RJ-45 socket matches the Diva PRI.  More information on cabling.

No RJ-45 socket:  If your Primary Rate line uses twisted-pair wires but the termination is not an RJ-45 socket, then you need to terminate the RJ-45 to bare-wire cable (included in some Diva PRI packages) with the correct connector, using the following description:

Coax cabling:  If your Primary Rate line is provided as two co-axial cables (sometimes called 'G.703 presentation'), then you will need to use a 'media converter' device to convert the co-axial presentation to the standard ISDN twisted-pair presentation.  

Suitable converters are widely available from under the names 'E1 to twisted-pair converter' and 'G.703 75-120 adaptor'.  If the supplier of your Diva board cannot help you with the converter, we suggest you search the Internet using these descriptions to find other suppliers. 

PRI lines in Malaysia, for example, have G.703 presentation so you will need a converter as described above.  

Also, check the twisted-pair presentation provided by your converter - is it I.431?  

More information on Primary Rate cabling.

3. Check that ISDN Line is still active

Most ISDN service providers will automatically 'turn off' your ISDN line if your Diva PRI is not configured correctly when you connect it to the ISDN line.  So always contact your ISDN service provider to make sure that your line is active before performing a test of new settings.

This need to re-activate the line after an incorrect setup has deactivated it is the cause of many apparent 'problems' with the Diva PRI. 

If you have the settings wrong the first time you connect the Diva PRI, then the line may well become deactivated.  When the correct the settings are subsequently entered, it still doesn't work. This is not because the settings are wrong, but because the line has been deactivated, so you may be tempted to go back to the first ('wrong') settings.  Then, even though the service provider re-activates the line, it goes inactive again because the settings are wrong once again!

So you need to make very sure that both the settings are correct AND that the line has been activated.

4. Start with the default settings for your country

Several critical parameters (including 'connection mode' and 'TEI' parameters) will be correctly set for you if you configure the country correctly in the Diva configuration.  Check with your service provider that the ISDN line is still active before testing the corrected settings. 

In EuroISDN (ETSI), the CRC is normally ON, so 'AUTO' will set the CRC to 'ON'.

Exceptions to this that we are currently aware of are as follows:

Dialogic's experience is that the CRC setting needs to be 'OFF' for Energis lines in the UK and Telecom Eireann lines in the Republic of Ireland.  Lines in France, Belgium and the Netherlands are also normally provisioned with CRC OFF.

For KPN ISDN30/Cityphone lines in the Netherlands, the CRC setting will be 'OFF' unless you asked for it to be on when the line was provisioned by answering "Ja" to the question "Alleen invullen bij ISDN30/Cityphone. Wilt u CRC-4 lijnsynchronisatie?".  The default answer to the question is "Nee" meaning "CRC-4 OFF".

Malaysia: Lines in Malaysia are not consistent in their CRC setting - some are 'CRC on' and some are 'CRC off', so you must ask the telco what the configuration of your line is (or try both settings, making sure that the telco has re-activated the line before every test).

5. Check for yellow status LED

This is the most common error indication from the LEDs on the mounting plate of the Diva PRI.

Meaning: 'Receive Remote Alarm'

Most likely reason: Wrong setting for CRC - the CRC setting must match the value configured for your line by your ISDN service provider.

Action: Check with your service provider the correct value for this parameter.   The EuroISDN (ETSI) default is 'ON' (so this is what 'AUTO' sets when you select EuroISDN/ETSI) but some suppliers require 'OFF'.  See item 4 (default settings) for more information.

Some ISDN service providers do not always abide by their own standards for CRC setting, so if you continue to get a yellow LED error, try both 'on' and 'off' settings for the CRC, but check that the line is still active first.

• For more information on the LEDs, click here.

6. Check the connection mode parameter

This parameter can be deceptive - it should normally be set to 'permanent' when connected to the public ISDN network (not to 'on demand' or to 'no disc').  Check that the line is still active before testing the corrected setting.

However, when the Diva PRI is connected to a PRI line on a private switch or PABXs, in some cases the setting 'no disc' may be required.

7. Check the XLOG trace

The following sequence, when discovered in a trace, and repeated many times, is typical of a wrong CRC setting.  This condition is often observed when the Yellow LED has only been lit for a few seconds and then goes out, so, if there are no LEDs lit and the trace looks like the one below, change the CRC setting from the default EuroISDN (ETSI) setting of 'AUTO' (which means 'ON') to 'OFF'.

25:2076:735 - L1_DOWN
25:2076:744 - L1_DOWN
25:2076:753 - L1_DOWN
25:2076:762 - SYNC_GAINED
25:2076:780 - L1_DOWN
25:2076:789 - L1_DOWN

8. Check whether your PRI line is a fractional line

A fractional line is a PRI line with a reduced number of B-Channels. If you have ordered a fractional PRI line, this needs to be configured specifically in the Dialogic Diva Configuration Manager, otherwise your Diva PRI card might not work as expected. For instructions on how to configure a fractional line, please see Using Fractional Lines.

Note: Supporting GSM calls

Calls from the GSM network can be presented as either V.32 (analog modem) or V.110.  In both instances, they require DSP support on the Diva PRI.