Had a supplier ask this

Custom or National ISDN ?

Can someone educate me on the difference please.\

Thanks

National ISDN is a NI2 and it is usually DMS100 emulation..
Custom protokol is usually 5ESS AT&T emulation.

Magority Telephone system uses ESF, B8ZS and NI2. But some of them like Avaya Legend require a Custom protokol instead of NI2.
Provider's setup and your switch setup MUST be exect match.

There are two dominant switching systems that provide the ISDN:

-Northern Telecom's DMS100 type switches
-Lucent Technologies [formerly a part of AT&T, now Alcatel-Lucent] 5ESS switches

Although both types of switches provide the same basic ISDN functionality, they differ in how they interface ISDN instruments (and other ISDN CPE devices) to the ISDN network. Custom and National ISDN are simply the 2 ISDN software types to adjust to these two switching system differences, and progress towards industry-wide ISDN standardization. This obviously makes it important to know which switch type (and corresponding ISDN software type) is being used to provide the ISDN services. Assigning/configuring the correct ISDN software type (Custom or National) ensures for full system compatibility and access to the entire ISDN network.

National ISDN is the current upgrade of ISDN services to meet an industry-wide ISDN standardization:

NI-1: National ISDN version 1 software, Standard BRI and PRI interface. However, a user may see differences in the manner in which a feature operates among different vendors’ products.

NI-2: National ISDN version 2 sofware, same as NI-1, but provides for more standardized operations for some features.


Custom ISDN:

For Nortel DMS:
-Custom ISDN MP only (Multi-point)

For 5ESS:
-Custom MP (multi-point)
-Custom PP (point-to-point)

Mike pretty much summed it up :bow: . One of the big features NI2 allows is caller ID. And as VAd mentioned, no matter what set up you decide to go with make sure you match what your provider is sending you. A circuit with a mismatched protocol may come up, but it will never work properly, and will cause you all sorts of grief.

ATT Custom does caller ID also

There are two types of Caller ID. AT&T Custom offers "number only", while National ISDN offers "name+number" CID.

....

I have a customer with a PRI that went from a Magix to an IPO with no changes to the circuit. They now get caller id name and number.

interesting...do you know what type of switch is servicing them?

Ipofficeguy is right. Magix doesn't provide a name even provider is sending it. That is why IPO is getting both.

Thanks guys for all the good info.

ATT (Formerly SBC) 5ESS from what I remember.

Boththe DMS100 & 5E support NI-1 & NI-2.

One feature that I recall with NI-2, mandatory 10 digit dialing on all outside calls.

FO

FYI, for some reason, McLeod couldn't provide name & number CID off a DMS100 in central Iowa, but NI2 could. Don't know if that was a protocol, provider, or CO switch limitation.

I also found out about the 10 digit dialing the hard way. I was off site when they rebuilt the circuit. I logged in and made a test call, but my cell was long distance to the site, so I didn't find out about it until people started calling me with problems.. :-D

I join Dane in thanking everyone for the different responses. Differences (and mismatches) between ISDN protocol variants have caused headaches beyond belief for many. I forgot to mention the "4ESS" (custom) ISDN variant for the 4ESS tandem switches.