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From "wire phone" to "IP phone"

For this purpose, there must be a "gateway" to connect the old PSTN = "Public Switched Telephone Network" and the newer IP network. The integration of both worlds makes the VOIP communication possible.


The gateway is a kind of hardware with an ethernet connection on one end and one ore more ISDN or T1/E1 PRI ports on the other end.


This can be a dedicated (high performance) professional PC server with an ISDN or WAN PRI card (i.e. 4 ports E1) or a router from the well known router companies like Lucent and Cisco and others. Here on the maxrouter pages, we mostly will point onto the Ascend products MAX 6000, MAX TNT and APX 8000.


There are lots of proprietary systems on the market. As a decisionmaker, the price and the support for new features and bugfixing is really important. For us, the reliability and reputation of the selected hardware is as important.

The gateway and the software

Gateway and Gatekeeper must be like brothers, the are talking heavily and all the time under stress. So they must be "friends".


You must take care about the seamless communication of these units. So evaluating a gateway not looking to the software but looking on the price is a big mistake.

What you need and what you get

The MAX 6000

If you like to start small, choose a MAX 6000 with VOIP and multivoice enabled by hashcode. You may have up to 4 fully working WAN PRI ports with E1 (or T1) and up to 6 slots for DSP boards with 16 ports (channels). So you may expand up to 96 VOIP connections. This one is very good and reliable for the far end in a far away foreign country. It is absolutely stressfree and reliable. (The MAX 2000 and 4000 cannot run VOIP.)



If you know in advance that there will be a need for more channels, you should start with a MAX TNT with one 8 port E1 PRI card and one 96 channel DSP card. There are some different models as DSP cards. This will be explaned on a separate page.


The MAX TNT has one 100 Mbit/s network port and a maximum of 4 8port E1 cards. If you may rent simple E1 PRI ports from your telco, as we know, then you will have 30 x 8 x 4 = 960 channels. If you are running the SS7 protocol, you will have one E1 for SS7 handshake and (8 x 4) -1 = 31 ports with 32 channels each = total of 992.


When our calcualtion is done correctly, you are using a netto bandwidth of 24 MBit/s on your 100 Mbit/s ethernet line. We dont know exactly the percentage of overhead. But this should be sufficiently ok for one MAX TNT. As well the TNT´s backplane should handle this traffic including all internel prattle.


However, there is a DS3 card for the MAX TNT too, running at 43 Mbit/s over a coaxial connection. This is similar to channelized T3, not E3 ( with 34 Mbit/s). As we got told, older or smaller PSTN voice switches like the Ericcson dont have DS3 at all or you must pay much much more than 32 E1 PRI ports with SS7 signaling. We own these type of cards here in Germany, but dont use them.



The APX 8000

We did not meet an APX 8000 up to now, because we are serving the dropped Ascend product line frm Lucent.


As the pictures show, the APX shoud have a dual bus system like the Cisco 7513 and the Nortel Centillion 1600 and the Marconi Fore ESX 4800 and a lot of other boosted units, created from a smaller model.


We will continue the specs of the APX here shortly.

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