What OS Do you use for Asterisk?

Hi guys,

I find that the girl sounds like she stutters sometimes. I’m using a P233 using Redhat 7.3 now.

What OS do you guys use to avoid stuttering?

Any idea on how to fix it or is it just a new OS that I need?

Does anyone get crystal clear voice quality over the LAN to Asterisk with the default congrats sound file?


Stuttering is probably because your CPU is doing something else at the time. Your CPU is kind of underpowered. I doubt that an OS change will change anything. You did not mention how much memory you have. I am guessing not much. That could also be a contributing factor. Do you know if your Hard Drive can run in DMA mode or just PIO. Does your HD light flicker when you hear the stuttering? Have you turned off EVERYTHING not absolutely necessary in the BIOS such as USB, Serial & Parallel, Audio etc.? Are you running AMP, Asterisk@home etc. they use web and SQL servers which could also contribute to bogging down a slow CPU, using memory, increasing disk access and network card IRQ hits etc.

Thanks for the reply
whopping 64MB of RAM

Nothing else is really running…no AMP, no MySQL
The HDD is running in DMA mode

It doesn’t really stutter after recompiling with the PROC=i586 flag and if I don’t leave a program like top open it is much better now.

Still it isn’t perfect, can you describe how the default girls voice sounds to you over LAN? I’m trying to figure out how clear/good it will sound if I were to use a better computer.

Lots of people say they are using a P166 and can do 4 conversations at once and I don’t hear them complaining so I wonder if they don’t notice or don’t care :smile:

I don’t think 64mb is enough for a standard RH install. You should probably have 128minimum, 256 for more than a few extensions, trunks. You can try running Astlinux which is designed to run in a much smaller footprint of storage and memory. If you don’t want to upgrade your memory and want to roll your own install try something like Debian. Maybe Pebble Linux.

It sounds at least as good as it would if it were a tape recorder at the other end of a phone line - e.g., an answering machine. Taking into account the fact that the format of the sound files isn’t exactly hi-fi, it sounds as good as you could expect - and no stuttering.

Yeah, well… People say all sorts of things - it doesn’t mean they’re true!

64MB is not much RAM at all to run a modern operating system in. For something like asterisk, i’d recommend having sufficient ram that you don’t have to have a swap partition. That way, you’ll never get latency problems due to paging in and out. For a single user system, 512 should be plenty. But don’t forget - no Xwindow!

Also, what phone are you using? If it’s a softphone, then that’s as likely to be the source of the bad sound as the asterisk system. If you want good sound quality, use a hardphone.

Hey guys,

Thanks for your responses. I have to agree it appears 64MB of RAM is not enough since at the moment there is 856K free memory. Of course there is no old DIMM on the market I can use because it is not using SDRAM even so upgrading is not a possibility unless I buy a new system.

I am not using X-Windows and I did the most stripped down install possible.

I personally believe CPU power is more than sufficient because the CPU power that asterisk uses has never gone over 2%!

After I recompiled using a special PROC=i586 flag the sound has basically been perfect as WillKemp describes. There are occasional and very slight blips but almost never.

I suppose it would happen when RAM is being swapped for a small second.

I guess I’ll have to hold it out for now unless I can tweak the Kernel to remove USB support and other stuff.

I’m sure if I had more RAM it would run perfect, CPU power is not the issue after watching the stats in top.

Thanks again everyone for the suggestions. I will try stripping out the kernel when I get a chance!

Wow! I disabled a ton of non-essential services and I have 35MB free of RAM…before starting Asterisk I had 45MB free.

I really hope that someone would prove me wrong, but after a lot of experimentation, this is my conclusion.

There is absolutely no way to get anywhere nearby audible audio without some sort of DSP board. The statement about Asterisk not necessarily needing voice hardware board is a lot of bull. Sure you can play without having to buy a Digium board, but if you need to have a minimum of the quality expected in a business setting, you need voice hardware.

I am talking about the playing of a *.wav file, because if you have a person in extension A talking to a co-worker in extension B, the DSPs are inside the SIP phones already, all Asterisk does is say “talk amongst yourselves”.

You want to have a crystal clear welcome greeting which reflects so much on the seriousness of your company. You won’t get it even with the fastest x386 chip playing the recording in software.

The OS choice is irrelevant here. We are talking about dedicated hardware vs. general purpose software.


When I say “play” in my posting above:

“Sure you can play” I am talking about “play” in the kindergarden sense.
Not in the “play, stop, FF, rewind” sense.


I’m on Fedora Core 4 with a 3.2 SMP P4 and 1.5 GB Memory (test system)

I run Asterisk with X-Windows and do a million other things at once (run a forum and mysql, postgre, etc.)

It comes out great.

I’m Lucky

Check out FC4, its wonderful

[quote=“Telephony”]When I say “play” in my posting above:

“Sure you can play” I am talking about “play” in the kindergarden sense.
Not in the “play, stop, FF, rewind” sense.


Now you have me really confused.

But back to your original post. There is absolutely no problem doing HiFi quality playback. A MP3 is a sound file; plays nice through the speaker.

Can you explain what exactly you want the DSP to do?

Opening a wav file, and transcoding it to whatever codec you have choosen does not take much cpu. A P233 should be able to do quite a few wav to g.729 transcodings. But you don’t even want that. For the highest sound quality you want ulaw or alaw anyway.

I would more suspect the hd settings (unmasqirq) and maybe the kernel version. RH7.3 is kind of ancient.