Which medium/high density voip gateway with fxs ports to choose?

Question

Asterisk

I would like to once again raise the topic raised in What do you think is the best way to connect ~ 200 analog subscribers to Asterisk? .
You need to connect 100-200 analog subscribers to Asterisk. IP phones do not roll yet:
- we do not fit into the budget
- not everywhere there is a normal ethernet
- a legacy from a bunch of analog faxes and phones
- there are normal telephone lines everywhere
The requirements are as follows:
- seamless integration with Asterisk
- analog line length up to 1.5-2 km
- connecting the gateway to the cross-connect via a multi-pin connector (a bunch of rj-11 does not roll)
- support for tone and pulse dialing
- support for analog faxes (T.38)
- reasonable price
- quality
I study products of firms: addpac, dlink, linksys, grandstream, eltex, audiocodes. So far, I have settled on the eltex TAU-32M.IP model for the following reasons:
- attractive price
- modular architecture. In case of failure, you can replace the burnt part.
Does anyone have experience with TAU-32M.IP or eltex products in general?
How is eltex with those support?
Whether there is an experience of operation of grandstream/dlink gateways?

Answer 1

Suddenly, someone will be interested: I decided to describe the implementation experience.
We settled on 2 models from Eltex: TAU-32M and TAU-8. In general, everything works stably, the TAU-8 had bugs with various additional functions in early firmware.
TAU-32M is the most expensive per port, but you can have rep. in stock. fund for them in the form of power supplies, chassis, FXS boards.
We use both models as a converter (adapter) from analog lines to SIP. All VDOs are implemented using PBX. In this configuration, everything works stably.
The need for T.38 is generally a moot point. Because at the border of providers, in fact, like the provider's network itself, it usually uses SS7. SS7 T.38s are not used. Therefore, regarding faxes, it makes sense to focus on G.711. Our faxes go with a bang on G.711 in the network of other providers.
The specifics of our company is that we have a large territory and a lot of buildings scattered over it. Therefore, the gateway was installed in each building. Before the IP building in the building is analogous. The result is a converged network. Not sickly saved on twisted pair between buildings in this way. When setting up QoS on switches, telephony began to go along with everything else, not only via optics, but also via Wi-Fi and VDSL bridges.
We tried to use TAU-32M to receive analog lines from the provider, i.e. FXO ports. The solution is workable. It is tuned intricately, but those. support helped. There were no problems with faxes via FXO. There was only one problem with the transmission of CallerID. More precisely, this is not even a TAU problem, but an Asterisk problem. The problem with CallerID arises when, in addition to FXO, there are FXS ports on the gateway. FXS and FXO ports are registered in Asterisk under their own users. Those. there is no single trunk between Asterisk and TAU. Then Asterisk tries to authorize calls based on the From field. Hence the problem with CallerID in FXO. If you disable the CallerID transmission, then everything will work. Or you will need to set up a single trunk between TAU and Asterisk.

Answer 2

Eltex TAU-72.IP, TAU-36.IP and Proteus MTU-A48 have no price competitors.
Modular gateways are more expensive per port.
I advise Proteus MTU-A48. They stand with a length of lines up to 2 km. No extra features are screwed up.
Eltex with support is fine, but sometimes it pumps up hardware (in the last batch of TAU-72.IP, power supplies "fly". They change without questions, but it takes time).
Dlink 16/32 FXS are operational, but there is trouble with faxes. There is no individual setting of ports for different softswitches.