Asterisk in entirely analog environment

I am new to Asterisk and from what I have read in the documentation and these forums it sounds like exactly what we need. We have 3 analog lines coming in and 8 analog phones. Will Asterisk work with this setup? I have seen a lot of information with IP phones with analog PSTN, but nothing entirely analog. I am planning on using 3 X100P FXO cards to connect to the PSTN and a Grandstream GXW-4008 8 port FXS Analog SIP gateway to connect the Asterisk box to the analog phones. I am sure the FXO cards will work, but am not so sure the GXW-4008 will work. Does anyone have experience with this gateway, or have any recommendations on the setup?


I don’t think you would want to use three X100P cards. Instead you would want one TDM400B cards with three FXO modules. With three X100P cards you would need three PCI slots on your motherboard that do not share any IRQs with any other device, and the echo cancellation on the X100P is nowhere near the quality you would have with the FXO modules on the TDM400 card. X100P cards are great for an experimental system, but I would not recommended them for production servers, let alone three of them.

The FXS gateway for the analog phone should work fine, although I have not personally tested the Grandstream model. I have used the Audiocodes MP-11X models and they work well.

I looked at the TDM400B and it looks like a great unit, but is a little pricey with all the modules. Do you have any experience with the sound quality on the Grandstream GXW-4104 or similar? It looks to be basically the same as the GXW-4008, but with 4 FXO ports instead of 8 FXS. I found them for less than half the price of the TDM400B with all modules. Also how is the sound quality with the Audiocodes MP-11X?


I have not tested any of the Grandstream multiport FXS or FXO gateways. I have not been overly impressed with the Grandstream devices I have tested, the BT-102, GXP-2000, GXV-3000 and a HT-486. They all work, but have some quirks.

The installations we have deployed with the audiocodes MP-11X, have worked well. I have had no complains of echo with them.

My experience in the VoIP market is you get what you pay for. Try and go to cheap and the experience will leave a bad impression of the technology. Buy the higher quality goods, and save yourself complaints and aggravation.

First, as superB said, X100 cards are fun to play with but you should never use them for anything important. They can cause echo problems, callerid problems, hangup detection problems, and wierdo problems that appear to have no cause. Sure they are cheap but as was said you get what you pay for.

I’d recommend the TDM400 spec’d out as FXO, yeah its more expensive but you get a much better product.

You might also try the xorcom astribank, its a USB-based channel bank that can be spec’d with both FXO and FXS ports. $/port cost isn’t too bad, and the drivers are included w/ zaptel.

Thanks for all of the information, this forum has been a great help. I will most likely be going with the Digium TDM03B 3 Port FXO and the Grandstream GXW-4008 FXS Gateway. This seems like the best of both worlds from a price/performance standpoint.


I hate to get in the way of a digium sale, but you really would save a boatload of cash if you use a network based call termination service. Even if you have to pay to have your number ported to them. Also, don’t muck around with FXS hardware, procure IP phones, or even use soft phones.

I have a few systems of different sizes. One is about like yours 4 folks in a sales office They had 4 4 line analog phones and 6 analog lines in a centrex. Each guy had a “private” line and two “public” lines.

The analog lines ran > $60 a month.

I replaced this with a ~$300 PC and 4 ~$80 phones. I paid $60 to have the number ported. They now get up to 25 inbound calls on one number for 2.9 cents a minute. We also pay 2.9 cente a minute for outbound calls to the US and many other places.

The ROI on this setup was under 2 months. BTW, for a little office, I would now stick the asterisk server on a $90 netgear slug. I have one of these up and going and it is just tits for a small office.

Feel free to contact me off lien if you have any Q’s