Newbie: installing dahdi and libpri

I’ve installed asterisk on a centos 4.9 machine, all went fine. Do I really need dahdi and/or libri? The asterisk server is connected to a bog-standard adsl broadband router, nothing special and I’m using old-ish cisco ip phones which have been flashed to use sip firmware. My server won’t take dahdi (the kernel is too old) but it will install zaptel. Do I really need these two?

It depends: If You don’t wish/need to use interface cards for PSTN-Phones or trunks (analogue or digital) then You don’t need to install dahdi/libpri as far as You additionally don’t intend to use Meetme as it depends on dahdi.
Zaptel modules can’t be used with Asterisk 1.8.

pthread timing isn’t stable except possibly on the cutting edge systems, so you need DAHDI, except for very simple cases. 1.8 won’t support Zaptel.

Reflecting latest discussions/patches on the dev-list, timerfd should be stable at least in one of the next minor 1.8 releases.

thanks for the responses here. I would like to connect an analog phone line to the asterisk machine but not directly - I can’t justify £500 of pci card so I was going to try a cheaper external converter box, something like a sipura 3000. I wouldn’t need dahdi or libri for that would I? I’m new to all this so please bear with…

If the handset is connected to asterisk via an adapter like SIPURA the interconnection from the Asterisk-side is done via SIP. Thus DAHDI is not needed for communication purposes. It may be needed for timing purposes as david55 mentioned but this depends on the functions You’ll using on the Asterisk-side on the one hand and on the error-fixing for the other alternative timing modules (pthread or timerfd) on the other hand.

You will not need libpri. As I said, I believe for all released versions of Asterisk, installing dahdi is highly desirable. This might not be true when 1.8.7 is released. Without it, you can end up with voice announements and tones stalling and the meetme application won’t work.