We know that there are a lot of alternatives out there that can measure up to Digium's releases of Asterisk cards. Why Digium charges so much with their cards are beyond me, when for the same functionality and the same quality, customers can avail of alternatives for a relatively lower cost. Quality asterisk hardware need not be expensive.

Question is where? Where do we look for such alternatives?

First, are you even open? Being in the open source community, you should be. Techies have a mindset that whatever gear they're after, it has got to be good. But in order to be good, you have got to be established. Digium's done that. And now they charge their cards at rates they can dictate and control. Again, are you open?

If you are, here is a list of known good Asterisk cards that offer the same functionality as their Digium cards:

* Zapmicro

* Yeastar

* Rhino

* Sangoma

Those are the ones in my list so far.

Zapmicro offers a pin-to-pin compatibility with their Digium counterparts. Meaning if you have a Digium card already and would like to expand it with either FXS or FXO modules, you can buy Zapmicro's modules and have absolutely no problem making it work with your Digium card. This works vice versa. If you have a Zapmicro base card and would like to expand it by using modules, you can use your Digium made modules as well.

Standard drivers for Zapmicro's 4-port card, the ZMA400P, can be used with asterisk. Non-standard cards such as the 8 port version, ZMA800P, requires a driver download so you can make it work with Asterisk. It is a guaranteed working driver.

Yeastar's Asterisk cards are uniquely done for their own. The Yeastar TDM800 base card sports an 8-port capable card but only has 4-ports physically present. What do I mean? See, their modules come in pairs. You have physically one module, but within are 2 modules. So they have a module with 2 FXS in it, 2 FXO's, and 1 FXO / 1 FXS pair with it. So there are combinations available as well. For starters, here are the module models:

* S2 - 2 FXS modules equivalent

* O2 - 2 FXO modules equivalent

* SO - 1 FXS and 1FXO equivalent

Don't get lost, it's pretty simple. If you want a 5 FXO card and 3 FXS card, use this config: 1 TDM800P base card + 2 O2's + 1 S2 + 1 SO. Got it? You should. Yeastar cards are not pin-to-pin compatible with Digium and you would need to download their driver from their website in order for it to work with Asterisk as well.

Rhino asterisk cards are also for Rhino modules. They sport their own hardware for echo cancellation, which is very important for VoIP applications. Echo cancellation basically is a method of removing noises caused by IP traffic and other factors that are involved in a VoIP telephony transaction. Texas Instruments make their echo cancellation chipsets. Rhino manufactures both analog and digital cards, as well as industry scale channel banks (a lot of FXS or FXO found inside an external box!).

Lastly, Sangoma cards are known to be expensive but reliable. Not that the other cards aren't, but they sure give that impression with their "Because it must work" tagline. Sangoma is an established engineering firm and have designed their cards to be justified with the reputation the company has. If you've got the budget, go!

Now, where do you buy these?

There are plenty of online stores that you can choose from when purchasing VoIP hardware. I've found one interesting though. PBXEQ.com. Unlike any other hardware store, the site gives a customer focused appeal, instead of the usual "Get the hardware you need and leave" kind of thing. The site also features live chat where you would have to simply click and you get a customer representative on the other end who is knowledgeable with the hardware they are selling. The site also features other VoIP products such as IP phones, gateways, Analog Telephone Adapters, and the like.