Tech Notes
Ask the Codec Answer Guy
Questions and Answers:
Q. I’m doing a remote at a location that has a digital phone system. There’s a jack right at the broadcast location. Can I plug my HotLine, Vector or Matrix into it?
A. If there’s any chance that this isn’t a plain old direct phone line, don’t risk damaging your codec. The high-tech solution would be to get an IBM Modem Saver or similar test gadget to test the line first. The low-tech approach would be to bring a cheap "plain old phone" along, and see if it works. If you get normal-sounding dial tone and can place calls, you should be all set. If the phone blows up, you have saved many bucks in equipment repairs. One other note: modems usually work better on direct phone company lines than on in-house phone systems.
Q. The phone line for our studio HotLine (Matrix,Vector) is also used for talk shows and the modem in the control room computer. Is this a good idea?
A. Go to the hardware store. Buy an inexpensive crowbar. Bring it back to work and use it to pry open the boss’ wallet, and then order a separate phone line for the POTS codec. Seriously, we highly recommend that nothing else be connected to that line. Make sure that your inside wiring is done with good twisted pair phone cable (Category 3 or higher computer network cable is great). If you must share a line with other equipment, try to actually disconnect the other stuff when you are using POTS codecs.
Q. I use my Nexus to do a talk show with a local radio station every Saturday. I want to do a show with a station at the other end of the state, but when we test the ISDN, I get a "Disconnecting" message every time I call them. They can dial me without problems. Help! Am I stuck being a local guy?
A. Not at all. Assuming there is intelligent life at the other end of your state, you should be able to communicate with it. You may not be signed up with a long-distance company for your ISDN line, or they might not have you set up correctly. We suggest going with one of the major companies for ISDN, as you stand a better chance of always getting your call through. If you are signed up already, call their data support numbers: AT&T (800-367-7956), MCI (800-283-6272), or Sprint (800-546-3282). If you use Fred’s Long Distance, be aware that Fred has ISDN tin cans but is still using analog string.
Q. The phone company just changed our area code. Do I have to re-program the SPID numbers in my Nexus or Envoy?
A. If your ISDN SPID numbers contain the area code (most do), you will probably eventually have to change them. The telephone companies usually allow a grace period during which either area code will work. Just remember to do it, or some day the power will go out, and the Nexus or Envoy won’t be able to link up with the phone company switch. If you can update the area codes in your SPIDs and still get "OK" on the main screen, stick with the new settings. And please unplug the ISDN line before you change the SPIDs. You may get an error message otherwise. It’s in the manual. Sorry. The Codec Answer Guy just couldn’t resist saying that.
Q. What does "LNK C" mean on my Nexus display? I got this at a remote the other day and couldn’t make any calls.
A. When you start up an ISDN connection, the Nexus will initially show "LNK DN" until it does its first conversation with the phone company switching equipment. You should then see a series of other "LNK" messages, ending with "OK." If the Nexus sticks on "LNK DN," something is wrong with the line or your connection to it. Sticking on "LNK B" or "LNK C" means that the first SPID number is not being registered. Similarly, "LNK E" or "LNK F" indicate a problem with the second SPID. The SPIDS have to match exactly with the numbers programmed in the telephone switch. These intermediate "LNK" messages usually mean that you’ve made a typo or that the phone company has given you the wrong numbers.
Q. This audio codec stuff is great, but how do we get rid of the echo at the remote sites?
A. The concept is simple. Don’t send the audio from the remote back to the remote. Give them everything else they need to hear but not their own audio. This means that the "cure" is at the studio end, not at the remote. See Tech Tip 220 (Mix-Minus...) on our website or fax-on-demand system.
Q. Our station will be doing three days of remotes in Outer Snorovia. Will our HotLine (Matrix, Vector) work from there?
A. First, try to get a direct outside line, if possible. If you must use a hotel phone system, ask questions about how well modems work on those lines. Second, check your manual for Country Code settings. If there isn’t a specific one for that country, try the North American version first, and then experiment if you have trouble getting dial tone or receiving calls. Third, realize that the greatest problems may be in calling in or out of the country. If Outer Snorovia is connected to the rest of the world by fiber-optic cable, you will probably do very well. Satellite, old microwave links or old undersea cable will give the greatest troubles. Be prepared to try different long distance companies, and dialing in both directions. Fourth, the Codec Answer Guy reminds you that they call it "Snorovia" because of sounds made by their sleepy telephone workers.
Q. When I make a credit card call with my Matrix, how do I make it pause to wait for the "bong" or the message that tells me to enter the rest of the numbers?
A. Easy one. While entering the numbers, just use the QDIAL key to insert two-second pauses. You’ll see a comma on the screen for each of them. Same goes for the HotLine and Bluebox. With the Vector, use the "Insert Pause" key next to the screen.
Q. How can I find out about upgrades for my Comrex unit?
A. Ask us! The key information we need is the model name and serial number of your Comrex equipment. While we certainly can help you over the phone, the Codec Answer Guy would appreciate your faxing (978-635-0401) or e-mailing (techies@comrex.com) the model names and serial numbers to us, along with your phone number. We can then look up the repair and upgrade information on those specific units, and call you back. This will save you some time on the phone, and guarantee the most complete answer. Some of the upgrades are quite important, like over-voltage protection for the older HotLines. Others may not even apply to the way you use the product. Please be advised that we do not have any upgrades that cure bad phone lines. We do have some suggestions about how to deal with them. Take a look at Tech Tip 202 (Modem Line Checklist)..
Q. We have a lot of older Comrex stuff that came from a station we just bought. How can I find out if it works, and what I can use it for?
A. They should have clauses in radio station purchase and sales agreements that require manuals to be provided for all equipment! Anyway, Comrex has manuals and advice for all of our stuff, right back to the dawn of time (1961, by our reckoning). Just call us and ask for Tech Support. We can get you started. And if the gear was sitting on a shelf because it didn’t work, we can see if we can fix it. Unless parts are no longer available, we should be able to help.
Q. Somewhere around the eighth inning of our last two baseball games, our Vector has "renegotiated," with a corresponding hole in our play-by-play.
A. Hmmm... The Codec Answer Guy humbly suggests that you consider shorter phone calls. The modem in your Vector (Matrix, HotLine) works by negotiating settings based on all kinds of electrical characteristics of the phone circuits through which your call is routed. After a couple of hours of use, those figures may change, and you might do yourself a favor by redialing the call during a break in programming. This isn't a hard-and-fast rule; just a suggestion that may save you some troubles.
Q. SPID numbers give me a headache. Do you have a cure?
A. Yes, take two SPIDs and call me in the morning. (Sorry...) Actually, the SPID situation for us folks in North America is getting simpler. A few years ago, the telephone company people got together and established a simple SPID format for use on phone switches that use the National ISDN (1 or 2) software. That format is: AAA XXX XXXX 0101, where the "AAA" is the area code, and "XXX XXXX" is the local dialing number. In most cases, you will have two local dialing numbers for each ISDN line. If you are having trouble getting the "OK" on your Nexus or Envoy, you might want to try that SPID format along with the NI-1 switch type. Also, if you plan to use 112 or 128 kb/s data rates, you should enter the local dialing numbers (LDNs). While we will still continue to provide the older SPID information in our manuals, be advised that most of the new installations will have numbers ending in "0101".
Q. How can I get 33.6 kb/s modem connections?
A. Move next door to the phone company. Seriously, higher modem speeds do not necessarily make a better broadcast. Your goal should be to achieve the highest speed at which the modem operation will be stable. Since slower connect rates are more tolerant of errors, some judgement is required to hit the right spot. In fact, the Answer Guy is partial to speeds of 28.8 kb/s and lower, as all V.34+ modems seem to be more stable at those rates. Use the MaxRate to set a ceiling that works in your area. And ignore those Internet weenies who try to tell you that "faster is better." Sex and modems do have something in common...
Q. I am buying a Comrex Matrix. Will it work OK with my HotLines and Vectors?
A. Ahh. a steady customer! The Codec Answer Guy well knows the connection between folks like you and his paychecks! The Matrix will automatically realize that it is talking with a HotLine or Vector and will switch to the appropriate mode. Unless your Vector or HotLine is very new, or has been upgraded recently, you should contact us about an upgrade that will insure maximum happiness with the newer modem in the Matrix. Also, you may want to turn off the Error Correction feature on the HotLine, particularly when used with the Vector.
Q. When I reprogram the SPIDs on my Nexus, I sometimes get a strange error message, like 'SS62'.
A. Since ISDN was invented by aliens from the planet BZ8S, we are stuck with a few quirks from their culture. First, they speak only in acronyms. "SPID" is a sacred word there, and they thought they were giving us something of great value. Second, out of reverence to that sacred word, they never presume to reprogram their equipment unless they first pull out the ISDN line. You must imitate their example, and not change your SPIDs without disconnecting the line, lest the curse of "SS62" fall upon you.
Q. How can I find out about upgrades for my Comrex unit?
A. Ask us! All upgrade information is now on our web site: www.comrex.com/technotes/tn217.htm. If you prefer, send the model names and serial numbers to us via fax (978-635-0401) or email techies@comrex.com, along with your phone number, and we will let you know whether an upgrade is recommended.
Q. My power connector is flaky. Should I replace it?
A. If the power jack on your HotLine or Nexus has the letters “SWC” visible from the back of the unit, we would like to see it replaced. Otherwise (or if you own a Vector), a little cleaning will likely cure any intermittent operation. The most durable cleaning process is a two step operation. First, squirt a little solvent-type cleaner (such as Caig Labs CaiKleen 41 or Chemtronics Electro-Wash PX) into the power plug. Then insert the plug into the jack on the codec, and rotate the plug to wipe the contacts. Now remove the plug and squirt some Caig Labs DeoxIT into the plug, and repeat the wiping process. The DeoxIT coating will last quite a while, so you shouldn’t have to do this very often.
Q. I am going crazy trying to dial (HotLine, Matrix, BlueBox) calls with an external phone. The modems just keep whining. What am I doing wrong?
A. I won’t make rude comments about the modem imitating its owner but rather suggest that this is probably only an issue about timing. We recommend that you get the codec ready before dialing by bringing up the screen instructing you to dial with an external phone. Dial the call on the phone, and as soon as you hear the first ring, press enter on the codec and hang up the phone right away. Don’t wait until the modem at the other end answers, or the off-hook phone will become part of the negotiation. Also please note that the Matrix and BlueBox can take a 44 digit dialing string without the need of an external phone. The same is true of Vectors and HotLines with current software. If you have an older Vector or HotLine that won’t do this, contact us for the free upgrade.
If your questions hasn't been answered, please let us know and we will track it down for you. We can be reached at 800 237 1776 in North America or techies@comrex.com for email.
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