The issue is that there are many many businesses that are big enough that they need DIDs and shared lines but aren't nearly big enough for digital technology.
There is a gaping hole in phone services that stretches between about 5 users and 75 users. They need the features that T1/PRIs offer but don't need, and can't afford 23 channels. John On Thu, 2006-07-27 at 11:57 -0400, Henry Coleman [VoIP-PBX.ca] wrote: > Hi, I have implemented Direct in Dial Trunks (DIDs) in Canada using a > Mitel SX100 PBX in 1986 > but I would not advise you to use this technology. It really doesn't > offer any advantage over digital lines > The first problem is that the three or four digits that get passed to > the PBX must represent extension number directly or must be mapped to an > extension range (a feature not always available). > The second limitation is the number of simultanious calls > All in all, the technology is better left to history. > A digital trunk servicing each extension is far less expensive and > offers much more flexability. > I would see if you can port the existing number range to an ITSP (or get > a consecutive group of digital lines) > These trunks could then directly ring an extension and if unanswered > could be diverted to a receptionist > to take messages or go to Vmail. This is the basic functionality of > analog DID and is a "piece of cake" to implement with Asterisk. > > Henry > > > > > > [EMAIL PROTECTED] wrote: > > >That's what I don't understand John. This analog signalling is common in > >the US as well. The old TASCOM PBX that we have was built in Chino, CA. > >Analog DID lines seem to be commonly supported on the old as well as new > >PBXs (for compatibility reasons). I think this was done because the PBX has > >considered an autonomous unit: self powered and self provisioned, hands > >off by the Telco. The only reason I can think that Asterisk doesn't support > >the full version of DID directly is that no one has worked on drivers for > >the > >cards. Brooktrout seems to have some. This looks like a gaping hole to me. > > > >The E&M Winkstart applies only to E1 digital connections. Sure DID is > >supported on Asterisk, but only in terms of the dialing protocol. Anyone > >else > >have any insight into this lack of support for the full DID trunk line > >circuits? > >Are we talking legacy here? Is ISDN expected to fill the gap? If so, this > >cuts > >out support for small message service businesses (in some locales) that > >can't afford a T1/E1. Of course, the digital deals are probably better in > >other > >markets. Maybe T1s are less that $1K in the larger cities. > > > >Thanks, > >Peter M. > > > > > > > >>On Wed, 2006-07-26 at 16:23 -0300, [EMAIL PROTECTED] wrote: > >> > >> > >>>Perhaps some of you are not aware of how the old DID lines work. When the > >>>incoming call > >>>is transferred to one of these trunks, 48 volts must be present. The CO > >>>switch seizes the > >>>line and polarity is reversed by the PBX to indicate ability to receive > >>>the call. This is called > >>>wink start. Four digits from the bank of DID numbers are then transferred > >>>and the call is > >>>connected. It is a standard ability of a real PBX since it has been > >>>traditionally assumed that > >>>DID trunking can be handled by a PBX. In fact, a lot of the new IP PBXs > >>>out there do this > >>>form of DID, also known as DID-over-analog. A few of these lines are much > >>>cheaper to run > >>>than a T1. That's why I'm disappointed that there doesn't seem to be any > >>>direct support for > >>>DID cards on Asterisk. We have two sets of these trunk lines to support > >>>but it needs to > >>>function for the messaging service to start. > >>> > >>> > >>According to > >>http://www.voip-info.org/wiki/index.php?page=Asterisk+config+zapata.conf > >> > >>Asterisk supports the following signalling types: > >> * em: E & M Immediate Start > >> * em_w: E & M Wink Start > >>... > >> > >>The description you gave above seems to be E & M Wink start. > >> > >>I hadn't been aware of this type of signaling until you brought this up. > >>Is it commonly available in Canada? > >> > >>John > >> > >> > > > >******************************************************** > >Peter MacFarlane, ACP > >Network Administration & Programming > >Target Call Center/ Message Centre P.E.I. > >***************************************************************** > >OpenBSD's PF Firewall: Now available with CARP Failover. > >Nothing to do with fish, but everything to do with security! > >***************************************************************** > > > > > > > >--------------------------------------------------------------------- > >To unsubscribe, e-mail: [EMAIL PROTECTED] > >For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > >
