In the part two I covered transmit and receive volume and DTMF Relay. In this last part we roll up our sleeves and look at some tcpdumps in Wireshark. This is how we can identify issues and remedy them with the past two articles.
Archive for the ‘Telco’ Category
This is part two of solving problems with VOIP and fire alarm system panels. The first part can be viewed here http://www.bohack.com/2012/04/how-to-solve-common-problems-with-voip-and-fire-alarm-systems-dialing-out-part-1/ I covered several common problems like POTS lines, on-hook voltage and VOIP quality settings.
In this series I will cover common problems with VOIP and fire alarm panels that are connected to an Adtran ATA or Analog Telephone Adapters. Specifically panels that need to dial outbound, inbound requirements and adjustments are somewhat different.
I will try to explain wiring of a T1/DS1 circuit end to end; since so many people have emailed me on the prior T1 wiring article and wanted more. In this article you will find references to the standards and technologies that surround a T-1/DS-1 installation. I will start with the line coming in and ending with the device. You may not have access to everything I explain, but there is a benefit in knowing the technology.
Recently I needed to connect to a Cisco router and didn’t have a serial cable on hand. The Cisco routers just like their switches come supplied with a console port built in. This console port is usually a female RJ-45 in the back of the unit and is labeled console. A lot of other manufacturers also use this method to connect to their equipment; everything from Sun servers to appliance servers.
Again I find myself wiring up T1 circuits for a Telco provider that my company is going to use. I also find myself scouring the Internet for color codes for the T1 cable at the “Smart Jack”. The smart jack is where the demarcation point or demarc resides. So what is a demarc and what exactly is the smart jack… The demarc is where the Telco ends their responsibility and yours begins. The Telco needs a way to start your responsibility for wiring and internal maintenance, that is the threshold of the demarc. The smart-jack is a way that the phone company can loop or loopback the signal so that they can remotely check that everything is OK on their side.
Well you really can’t find out where someone lives exactly, only the phone company can tell you that and that information is confidential. However you can find which town someone lives in using the NPA/NXX database. The North America Numbering Plan was first introduced in 1947 and adopted by AT&T in 1951. The NANP was made to simplify and speed up long distance calls or calls that needed to leave the Central Office they originated from. That is where ‘Mabel’ would get on and you would ask to connect to Bayside-0213, Bayside was the central office or ‘229’ b=2 a=2 y=9 or you could ask for 229-0123. The letters on the phone are there for a reason and that was when the NANP came into existence.