Due to the compression issue on VoIP many analog data services (modem/fax/etc) don't function _reliably_. Making sure you use a codec that does not compress and removing error correction can help but still does not guarantee success.
As for alarm systems. Some companies now offer TCP/IP communicators that send the same signals over IP to the central monitoring station as due the analog communicators. DSC is one of the companies making such devices. However, you must have a monitoring company that supports the data coming in over IP. There is also a different pricing structure for this service. At our church, we ended up going with a cellular communicator instead because the price point was lower than using the IP unit. -dbc. -----Original Message----- From: Dean Yorke [mailto:[email protected]] Sent: March-06-09 7:53 AM To: Jim Van Meggelen Cc: asterisk Mailing Subject: Re: [on-asterisk] alarm systems Jim, Thank you for that very clear definition. The issue though is trying to get a voip line to support an alarm (which seems to be no issue now) and a postal machine. Apparently, the postal machine does some special look on the line for um......... It doesn't work like a fax or modem. So, it doesn't pickup the line, look for dialtone and then dial. it apparently picks up the line and looks for some noise and then initiates communication. All I know is that it definitely does not work with ata and voip lines. So, I am looking for clarification so I can get around this. Thanks On 6-Mar-09, at 12:34 AM, Jim Van Meggelen wrote: > There seems to be some misunderstanding here. > > This is probably the best way to understand a local loop: > > The local loop is the pair of copper wires that run between your > premises and the Central Office, through which the carrier delivers > a service. The carriers generally refer to all this collective > copper infrastructure as the Outside Plant. I suppose a local loop > could be fibre as well, but I think most people would be best to > think of a local loop as a copper connection. It is pretty much pair > of wires that run from your premise to the circuit terminating > equipment provided by your carrier (there may be some cross-connects > along the way, but that loop is dedicated to your premises). > > - If they connect your local loop up to an analogue card, you get an > analogue line. > > - If they connect your local loop up to a DSLAM, you get DSL. > > - If they connect your local loop up to an HDSL unit such as a > PairGain, you get a T1. > > - If they connect your local loop up to some other thing, you > get . . . um . . . some other thing (I'm thinking mostly of old > services that nobody ever orders anymore). > > Traditionally the carriers would--by default--connect copper loops > to analogue circuit packs, and then simply program the circuit up if > you want dial tone. This is why a dead line will often have battery > (which means there is voltage on the line and you can hear sidetone, > but no dial tone). A 'dry loop' refers to a loop that has been > disconnected from the analogue circuit, and not provisioned for any > traditional carrier services. If memory serves correctly, it's > called 'dry' because it's disconnected from the batteries (which are > 'wet'). It's really more of a pricing and tariff thing than a > technical thing, since they may not bother actually disconnecting > the wires. The point of a 'dry loop' is that you are having DSL > delivered on a line that would typically also have an analog circuit > on it. > > Does that help? > > Note: Local Link is a bundle of features that are delivered on an > analog circuit. "Link" refers to the fact that you can press the > "Link" button on old Nortel phones to perform a hookswitch flash. > Local Link service offers all sorts of features that you access via > the "Link" button. Since Bell and Nortel were once the same company, > Bell uses a lot of Nortel-speak. You can also get "Link" type > features on your home phone. Bell just doesn't call that "Local > Link" even though it might be very similar or even identical from a > technical perspective. > > Clear as mud? > > Jim > > > Dean Yorke wrote: >> Hi All, >> >> I know that this might be a little off topic but....... >> >> Wondering if someone can help me understand the difference between >> an analogue line and a local loop line from bell. >> >> we have a couple pieces of equipment, (pitney bowes mail machine >> and personal install alarm system) that are having issues >> communicating on these lines. >> >> Thanks >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [email protected] >> For additional commands, e-mail: [email protected] >> >> > > > -- > > -- > Jim Van Meggelen > [email protected] > http://www.oreillynet.com/pub/au/2177 > > "A child is the ultimate startup, and I have three. This makes me > rich." > Guy Kawasaki > -- > > --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
