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Trouble shooting Dialers
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Trouble shooting Dialers

Technical support requests are common place for dialer transmission issues.  With the physical infrastructure changing from copper to other transmission mechanisms, problems are encountered on both new and old installations.

The ability to accurately troubleshoot transmission issues revolves around having the correct tools.  It is imperative that technicians carry a portable telephone monitor otherwise known as a ‘butt set’ along with a multi meter.  The ‘butt set’ tool allows the technician to actually monitor one of their phone lines in order to determine if the call is actually being made to the central station receiver and a data dialog occurring. The multi meter allows an easy way to check line voltages both on-hook and off-hook.
The simple listening technique of a butt-set will allow a technician to determine

  • if the call is being attempted and if to the correct number by the fact of the receiver answering
  • if data is being transmitted in either direction
  • if a ‘receiver handshake’ is ever being responded to

The majority of times, knowing how far your data transmission gets in the complete cycle will allow an accurate trouble shooting plan.

A common support inquiry which we receive is a dialer which misses the daily test call every other day. 

Dialers are made to send test calls on alternate lines each day, and if that line fails dialer will not try the alternate.  VES dialers use the zone field to indicate which lines the test call originates from.  By inquiring with your monitoring center, easily you may determine which line the signals are being received from.

In order to assist in further trouble-shooting we have included some basic knowledge pieces:


Daily Test Signals and Telephone Troubleshooting
Traditional POTS (Plain old Telephone Service) is the telephone service type which digital dialers were actually designed to operate under. In order to troubleshoot the line you must know it’s characteristics.  The average voltage for a traditional POTS line is 48VDC. When you go off hook on a phone line the voltage drops to somewhere around  4-18VDC.  It is important to know that you must have a RJ31X jack when connecting your fire alarm panel to the phone lines.  As most everyone knows you must have two phone lines for a fire alarm system. One line must be dedicated and the other can be shared providing that you have line seizure.  The diagram below shows a traditional line seizure on an RJ31X jack.


http://www.hometech.com/learn/el-rjset.jpg

One reason for phone line trouble is that there is no line seizure on a line and the control panel cannot dial out. This usually happens when the shared line is used and the operating voltage falls below the normal operating voltage for the control panel.  There are current regulators that you can use, but nothing is cheaper and more efficient than traditional line seizure.

Here is a list of things you can check for when you have phone line issues

  • Verify that you do not have a loss of service from your phone line
  • Check for shorts and opens from your control panel to demarcation box. Tighten terminals
  • Unplug the Alarm system from the jacks and identify if it is the panel, RJ31X or, the service itself.
  • Check with the customer to see if anything was changed with the Fire alarm system phone lines. Sometimes the customer can change over to a Digital or VOIP configuration without telling you. This can affect an alarm systems transmission capability.
  • See if toll restrictions were lifted and you do not have a toll free number dialing to central station.
  • Check and see if a system was moved behind a PBX or some other item which has affected the necessary dial string.
  • Check the Monitoring Center account is correctly configured.  A common error is the transmission protocol (SIA 20 or Contact ID) for the account does not match what the panel is sending, which can prevent proper handshaking and signal processing.

It is recommended that your customers know that traditional POTS lines are the best for alarm systems.  While other technologies are being deployed for telephone service, there is no one rule of thumb on what will or will not work outside of POTS service.  Each of the different hybrid technologies operate in different methods.

One of the alternate technologies Voice over IP (VoIP) uses a different technology than that of POTS. VoIP is a technology that allows you to make voice calls using a broadband Internet connection instead of a regular (or analog) phone line.  Many times your customers, when making the decision to utilize VoIP do not understand the ramifications of the change. Delays in transmission and alternate voltages may in fact create performance issues with Digital Alarm communicators.

One of the other important things to note with regard to VoIP is that if the customer’s house or business losses power (without adequate backup) the system will not send any signals because communications are powered by the premises rather than a telephone company central office.

Also, with a VoIP line if used will not by itself adequately seize the line regardless of wiring. If you see this in the field, you should use a BW-1 or similar connector for line seizure.

While many issues can cause communication troubles with your monitoring center, communication records / logs and basic tools should assist in isolating the trouble.


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