Step 1: Rebooting your hardware

If your circuit is down hard, either in an RMB or CFL state, it's always good to begin your troubleshooting by rebooting your multiplexer and/or CSU.

Tip The two pieces of hardware that are actually talking to each other on the circuit are your multiplexer and the computer card at your carrier that functions like a multiplexer, so rebooting the hardware on your side may resolve the issue. If rebooting brings your circuit back up, you should still follow up with the trouble ticket to determine the root of the problem. Most problems don't happen once and then disappear forever. If troubleshooting indicates a hardware problem, you ought to replace the faulty hardware while it's still limping along, instead of waiting for it to fail completely.

Rebooting your hardware isn't helpful for troubleshooting call quality issues, because they will generally be the result of something being set up wrong or a progressive failure in a section of your hardware. The first problem could be anything from a protocol mismatch to a configuration mismatch.

Here are some important rebooting do's and don'ts:

• Do make sure more than one person knows how to reboot the phone hardware. You and someone else in your office (your backup) should know how to reboot every piece of your phone system. It's a waste of time and money to call out your hardware vendor to push one button. If you don't know how to reboot your hardware, ask your hardware vendor to show you. If it's a complicated procedure, have the vendor write it in black pen on the wall of the phone room next to your hardware. It's well worth having graffiti on your wall to be able to confidently push a button without worrying what will happen (besides, graffiti art is cool).
• Warning! Don't be in the dark about whether your phone system will restore to default settings. It's uncommon, but not unheard of, for hardware to restore to default settings after being rebooted. When you discuss recy-cling the power of your PBX, multiplexer, and CSU (as well as any other servers or devices attached to these three pieces of hardware) with your vendor, be sure to ask about possible side effects of rebooting. While you are at it, also ask about fixing these side effects if they come up. The solution might be very simple, or it might be, "don't touch anything; just call me." Either way, this information is good to know.
• Do make note of the frequency of your reboots. If your circuit drops on a regular basis, be it once a month or once every three months, but immediately comes back to life when you reboot your hardware, your hardware might have a timing issue. A timing issue can be caused by your hardware utilizing a clock for the point of reference on your TDM circuit that doesn't come from your carrier, or the section of your hardware that handles the clocking on the circuit may be failing. In either case, timing issues cause the phone system to accumulate small slips within the circuit that eventually cause the circuit to fail. You might ignore the problem because your circuit comes back to life as soon as you reboot, but the issue isn't solved. It will progress over time, and the time it takes for your circuit to fail will gradually become shorter. If this scenario sounds familiar, contact your hardware vendor to check your phone equipment.