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ISDN E1/T1 for AskoziaPBX

Superior call quality and reliability for your business

If your are looking for the highest possible call quality in combination with a high call load, ISDN PRI (T1/E1) might be the right choice for your business. PRI is more reliable compared to VoIP because SLAs with your telephone provider mandate a quick response to fixing any issues. Whereas your DSL or VoIP provider can go down for days without you being able to do anything about it. On the other hand, costs for ISDN PRI are higher compared to pure VoIP telephony. With Askozia phone systems you don’t have to decide for one technology as all our PBXs are hybrid systems. They allow you to connect to the traditional phone network via ISDN PRI and use IP communication via the internet at the same time to reduce costs.

ISDN PRI (T1/E1) VoIP (SIP trunking)
Call Quality consistent consistent
Reliability high varying
Costs usually higher compared to VoIP unpredictable


Bottom line is, if your phone connection is mission critical and your business depends on it, T1 should be at least your fall back if something happens to your VoIP connection. The optionally available PRI software module allows the seamless integration of E1/T1 ISDN interface cards and gateways with AskoziaPBX.

What  do I need to use PRI? – E1/T1 at a glace

In addition to a PRI line from your telephony provider you either need AskoziaPBX software license with PRI module and supported PRI hardware or one of our ready to use phone systems with PRI from our online shop.

ISDN is divided into two types of services, BRI (Basic Rate Interface) and PRI (Primary Rate Interface). BRI is mostly used by smaller enterprises, PRI is meant for medium and large enterprises as well as smaller companies who require a high number of parallel calls. Both, BRI and PRI are consisting of B and D channels. B-channels carry voice, D-channels carry control and signaling information. BRI consists of two B-channels and one D-channel. PRI is often referred to as T1 (North America and Japan) and E1 (Europe and Australia). T1 usually has 23 B-channels and one D-channel, E1 usually 30 B-channels and 2 D-channels.

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On the cloud

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