Today let’s discuss the time honored problem of “I have a dead telephone line and who do I call"? Do I call my carrier, or do I call my telephone system vendor? The frustrating part of this decision is the 50-50 shot of calling the responsible party or worse, incurring a billable service charge from the un-responsible party. Due to the differences in services from different carriers, we troubleshoot them much differently. First let’s discuss the different types of service from carriers to better understand.
There are three basic types of service spread across three different mediums. Service types include POTS otherwise known as "Plain Olé Telephone Service", PRI or "Private Rate Interface", and SIP "Session Initiated Protocol". POTS is one set of copper pairs for each and every phone number you have. Symptoms can be one line dead but all others work fine. This is due to the unique nature of the copper pairs supplying each line.
PRI is a digital medium supplying as many as 23 talk paths called "Channels". It will come to your business on 2 copper pairs and feed into your phone system as either "Pure Digital" or broken out into individual analog lines through an IED or router. Symptoms are much different with PRI than POTS. PRI is typically what we call an “All or Nothing”. Since all the talk paths are bundled into the digital path, if the copper medium supplying all the voice paths is damaged, all the talk paths are down at the same time.
SIP is a totally different animal and fairly new and mostly used in major metropolitan areas but it spreading into smaller areas. A SIP Trunk provides the same service you get from a traditional analog phone line (POTS). The difference is, instead of being a physical wire, a SIP Trunk is a “virtual” phone line which is provided by a SIP trunk provider They use your data circuit (T1, Cable Modem, DSL, Ethernet over Copper, etc.) to connect your phone system back to their network.
As mentioned above, the three different mediums is copper pairs from an ILEC (incumbent local exchange carrier) like AT&T and CenturyLink , or a cable TV carrier such as SuddenLink or Mediacom or In rare instances, fiber optics to the premise. Most all offer the above forms of services.
So, with all that hot air, if this seems complicated and convoluted it's because it is! At ProTel Systems, we have no idea how to troubleshoot and fix your car, your microwave or your lawn tractor. What we do understand is communications, the players and how it's all tied together so when you pick up your phone and say "Hello Mom" the answer on the other end should be "Hello" back. On the occasion when it's not, the expertise of ProTel Systems will be able to diagnose which part is broken.
With our 100+ years of combined experience, we here at ProTel Systems are committed to helping our customers weed through all the Mumbo Jumbo over the phone to first troubleshoot and make reasonable decisions as to which fork in the road we choose for resolution. We always do this first, rather than going straight to a billable event and truck roll saving time and money. If necessary, a billable truck roll will always be the last resort when we and the customer mutually agree it is necessary!
See you next month!
ProTel Systems and Supply, Inc.