by Greg | Jun 6, 2012 | Testing
Fiber optic testing with an OTDR is a fairly straight forward process. When you’re talking single-mode fiber most customers require, at a minimum, testing each fiber at 1310nm and 1550nm windows to insure that splice specifications are maintained. When testing outside plant this involves an OTDR , a pulse suppression box (launch) , knowledge of the network and the know-how to use the test equipment. There are many, many man hours involved in testing and proofing fiber networks. Thus, it is important that time is well utilized and the data is collected properly. Although most OTDR’s manufactured today are very easy to use they don’t do the job for you. They are a tool to aid you in doing your job. We were recently sent a pack of traces for review for one of our customers. There was an anomaly in the 1550nm window data that they could not explain and the contractor that did the work didn’t have any answer for them either. The contractor actually said the fiber was bad. The anomaly (shown in the photo to the left) was caused due to the fact the OTDR being setup wrong by the technician. This particular OTDR has a macro event setting. It was turned on and for some strange reason the trace data had a false event imposed into the data. In all actuality there are no events at these points and the fiber cable was not damaged. Tips when using an OTDR: First, always use a launch cable. An OTDR pulses must traverse a minimum distance before the OTDR can take meaningful measurements. Always start with the OTDR set...
by Greg | Jul 25, 2011 | Equipment
Back in January I posted about a compact flash that was hitting the market as an upgrade to the CMA4000/4000i OTDR. Since then we have had one of our machines upgraded and wanted to give a short review of the flash drive. IMHO the CMA is the best OTDR every developed for testing fiber optic networks. The rugged exterior and the reliability of the equipment has yet to be match with todays OTDR in production. The draw back to all machines of that era was how the traces were transferred to a desktop computer. Choices were limited to a floppy drive or a par net setup. The shear number of trace data from a large network such as a FTTH project can take hours to transfer using a floppy. 1.44 meg isn’t that many files when your scan times are long and your acquiring multiple windows. If you own one you know what I’m talking about. Well, those days are over. The compact flash upgrade brings an old machine back into the game. File transfer headaches are a thing of the past. Here’s what you get when you upgrade ole Betsy; Compact Flash (replaces internal hard drive and floppy drive) USB Card reader/cord 2GB Scandisk There is only one thing you will need to train yourself NOT to do, and that is do not remove the flash disk while the OTDR is on. The card is not hot swappable! There is a big warning label on the inside of the floppy door lid reminding not to remove the card. Be very careful as old habits are sometimes hard to break....
by Greg | Jan 14, 2011 | Software
This short video explains how to use a ODTR trace viewer called Traceview to view trace files. This is a basic tutorial which shows the steps required to view a OTDR traces. It demonstrates how to add traces, set up the screen view, scaling the display range, setting A and B cursor locations and selecting loss modes. View OTDR trace files on your...
by Greg | Jan 7, 2011 | Software
If you use an older OTDR for fiber testing then you know how much of a hassle it is to copy trace files from the OTDR over to the PC. To put this into a little perspective, transferring a couple hundred megs of trace data off of a CMA4000 involves copying data to a floppy disk over 150 times. And to boot it’s a manual process that take up entirely too much time! The UPLOAD FILE(S) option on the mass storage menu of the CMA4000/4000i allows the user to select a large number of files and initiate a remote copy process without having to copy to a floppy, and then to a PC or database. To accomplish this there are two things that you need. A null modem cable and the software utility OTDRcopy.exe. The null modem serial cable required is a DB-9 female to DB-9 female serial cable with a 9 pin male to female null modem. The OTDRcopy.exe utility is a small DOS program that can run from DOS or from a DOS shell in the Windows environment. It can be found on the CMA upgrade diskette version 3.18a or later. Follow the steps outlined below to transfer trace data files serially from the CMA (version 3.18a or higher) to a PC using the OTDRcopy.exe utility. 1. Using Windows Explorer, create a directory or subdirectory on the pc named OTDR copy (or something easily recognized) in which the OTDRcopy.exe utility will reside. This is also the directory or subdirectory where the files will be transferred to. 2. Copy the OTDRcopy.exe file from the CMA upgrade disk to the...
by Greg | Jan 4, 2011 | Software
One of my counter parts has been having problems a CMOS checksum error with his CMA4000 OTDR . The problem manifests itself once the on board battery begins to fail. A checksum is computed as an error-detecting code, to protect the BIOS settings stored in the CMOS memory. Each time the system is booted this number is recomputed and checked against the stored value. If they do not match, an error message is generated to tell you that the CMOS memory contents may have been corrupted and therefore some settings may be wrong The technical description from Anritsu as to why the problem appears: The CMA4000 and CMA4000i have a small lithium coin cell that, in the absence of power from the ACAdapter or the main battery, is used to preserve the contents of the system RAM disk as well the BIOSsettings and the real time clock. The life expectancy of this battery is approximately 5-7 years. If sufficient power is not available to preserve this memory, the unit will report a bad CMOS Checksum or System Battery failure during the Power-On Self-Test. I’ve listed out the recovery procedure below. This is a temporary fix. To cure the problem the battery needs to be replaced. The Recovery Insure that a proper main battery is installed in the controller. Connect external power from the AC Adapter. Confirm that the Battery LED indicates that the battery is charging (or is fully charged). Please read the following information BEFORE attempting to reset the memory. Timing is critical and success will be insured by reading this information. a. Locate the following keys on...
