Digium TE121, single port VOIP card test

Currently, the market offers a great variety of digital boards focused on building telecommunications systems that can combine 32 lines of E1 digital streams with any form of telephony-from PSTN to VoIP. Today we will test one of them and tell you about its results.

Choosing the E1 digital phone card for the test, we decided on the TE121 single-port card from the American company Digium, since this developer is the manufacturer of the most popular and widespread Asterisk platform in the world.

The TE121 card can be used to build a telephone network and provide subscriber services such as IVR, voice mail, and conference calls. During our testing, we will use the Digium card as a communication device for an IP PBX with a telecommunications provider that provided us with E1 digital stream lines — both for voice and data streams.

Let's go to the SOFTWARE selection. There is no point in checking the map again for compatibility with the Asterisk platform, since this is already obvious. Therefore, choosing from Russian SOFTWARE manufacturers, we decided on the Mototelecom IP PBX ™ system as the most optimal product that combines broad functionality and affordable price, and most importantly-ease of configuration.

Digium TE121 Package Contents

The card is supplied in an OEM configuration. This means that you will not find any drivers or documentation in the box, only the device itself and the Board with the RJ-45 port. In our case we got a separate TE121 card:

Digium TE121

and a separate echo cancellation module in an envelope with a traditional warranty label:


The package includes a full-size "plug", which has built-in light indicators that display the current state of the stream. But, in our opinion, a low-profile "plug" would also be useful in the kit, since its absence can make it difficult to install the card in some servers.

Echo Cancellation module

The echo cancellatio module (VPMADT032) is designed as a removable Board that can be disconnected from the card. According to the manufacturer, it is able to successfully suppress echoes of up to 128 MS on 32 channels simultaneously when using the E1 interface and on 24 channels when operating in T1 and J1 modes, respectively.

Echo cancellation module

The card has a jumper for switching between digital data channels T1 and E1. However, it is not very conveniently located-under the map of the echo compensation module, so to change the flow type, you will have to disable this module and move the jumper.

Digium TE121

This, however, is not so important, since in Russia the E1 format is mainly distributed, so it is unlikely that you will have to switch from stream to stream, except in the case of a change of provider.

Model range

The model range of single-port Digium digital cards is impossibly simple: the TE121P is easily converted to TE121B by adding an echo cancellation module.

Card with echo cancellation module

TE121 testing

Installing the TE121 PCI-E card into the server took us only a few minutes and did not cause any difficulties. Step-by-step instructions for installation and configuration are available on the official website of Digium in the public domain. Here we had to apply our knowledge of English, since the Russian version of the documentation is not available on the site.

It took a few more minutes to install the drivers, the complexity of which obviously depends solely on the Linux implementation. Then, in the open window of the Mototelecom IP PBX ™ program, we launched "Search for new cards" so that the system could see our card.

After completing all the preliminary settings, we moved on to testing the signal of both incoming and outgoing calls on the E1 line. After careful "listening", we concluded that the sound quality in all respects is not inferior to conventional analog telephony.

To complete the picture, we conducted additional testing and "parallelized" 30 streams into 15 voice and 15 data streams. The sound quality remains the same, and the data transfer rate remains the same as stated.

In order to make the picture as complete as possible, we conducted additional testing of the map functionality, which also confirmed all the characteristics declared by the manufacturer.

However, we did not limit ourselves to a simple study of the installation and operation of the Board, and as an experiment, we removed the echo compensation module from it in order to track the differences in sound quality in its presence and absence.

Removing echo compensation module

However, since the testing was performed on a high-performance server, we were not able to feel any difference.


The card is designed based on Digium's VoiceBus technology that uses the standard PCI Express bus, so it can be embedded in any of the available PCIe slots v1.0 (x1, x4, x8, x16).

Fee TE121 eliminates the need for an external network router, because it supports simultaneous voice and data over a single interface, through which can occur parallel processing 15 dedicated voice channels and 15 data flows. Thus, we can use only the part of the streams we need instead of all the available ones.

In the case of using the Asterisk platform, specialists can view the system status, group in time slots, and simultaneously call a group.


The TE121 card met our expectations during our testing. It is really easy to install, configure and use. The use of the Mototelecom IP PBX system made it easier to operate the card and allowed you to get good sound quality on each of the E1 data channels.

And, of course, in conclusion, it is worth Recalling that technical support FOR te121 from Digium will be available only after the product is registered.

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