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Do you have problems with this Ascend (Lucent) MAX 1800 ?

The MAX 1800 looks very similar like to a MAX 2000, but on the display on the left front side you see WAN1 to WAN8.

The frontpanel

The MAX 1800 can handle 8 RJ45 ISDN (2 x 64 KBit) ports (16 ISDN channels) and a maximum of two digital Modem cards. There are BRI-s and BRI-U versions.


Dont clean the front panel with alcohol or similar fluid, all printed characters will be lost, forever, so take care, use water with soap.

The features

The MAX 1800 is a longlife product. Our two units are 7 years old and working woundeful. It is one of the older ISDN 8 x BRI Products and its EOS (end of sales). Even in 2003 we get more and more requests to sell a 1800 BRI-S and !! BRI-U, running Euro ISDN perfectly well.


The MAX 1800 can be used as "dial in", "dial out" and "nailed line" router and a mix of that. It handles all dial calls with a Radius Database accountig system very reliable. The TAOS software is bullet proof and did grow over years to nearly perfect solution.


However, the MAX 1800 has a 2 Mbit serial (x.21) port. We did never use that port. There is a x.21 option as a hashcode, to enable this port. Firstly we do not know, if the option will be anymore sold from anyone, we did never test it.


Secondly the MAX 1800 withits 12 Mhz CPU was never built for X.21 use. It was a BRI dial in / dial out router and we did use it as a nailed line router. This works really fine and you should us it as it was planned for.


There are two ISDN interface versions on the market, the BRI-S and BRI-U versions. In Europe, we are mostly running the BRI-S (the well known S0 interface). This is the 4 wire ISDN cable behind the NTBA, where you can connect up to 8 ISDN devices.


The BRI-U version is the two wire version, where the NTBA is included/substituted inside the MAX. The MAX-1800 has a 12 MHz Intel I960 CPU. There are now known critical problems.

We are running a very old TAOS

To show, what TAOS we are successfully running (here in Germany) for years without a need of an update. It is old and it works fine, really fine, for years. We have 64K per single ISDN channel.

The rear side

This is our own running MAX 1800 for test- and service purpose. The 12port Modem Card is on the left side.

Our MAX 1800 (above) works very reliable over years. We are using one from late 1996 on. We use one MAX 1800 with a 12 port S56k digital modem extension board.

However, there are two slots for cards. It runs day and night and works fine, a workhorse. For us it is the very reliable top reference class for any "Dial in" ISDN router.

One strange disadvantage

We did change from an MAX 4000 E1 PRI dialin to an MAX 1800 with 4 ISDN BRI lines with 8 channels, to save costs in 2005. We did use the same modem board with 12 digital modems as in the MAX 4000. But from now on modem access was unacceptably slow. We didnt find the problem. Any hint is welcome.

Watch the type of the MAX, it may be BRI-S or BRI-U

There are two types of MAX 1800 WAN port interfaces, called S and U interface. These WAN ports are completely different and they are not exchangeble, but the TAOS is the same.

the S type
the U type

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