oberman@ptavv.llnl.gov (05/30/91)
Well, a government agency (or its contractors) has again forgotten
about those silly, old-fashioned rotary phones. This morning's
{Tri-Valley Herald} (Livermore, CA) reports that a $25,000 telephone
messaging and information system installed in the county courthouse is
not accessible by rotary-dialed phones. "Those unfortunate enough to
have the old-fashioned types of telephones will be disconnected five
seconds after the menu of keypad choices ends."
The system for the small claims and civil divisions was supposed to
switch to an operator if no menu items were selected, but "somehow, it
got lost in the cracks" said John Reymundo, division chief of the
small claims court.
It's not clear who is responsible. Craig Watts of Pacific Bell is
quoted "That is bad." and "I sure hope it wasn't our system." and
claimed that 23% of California households have rotary phones. (First
time I've heard that number. I wonder where he got it.)
The company who installed the system was unavailable for comment.
(Gee, I wonder why?)
I wonder how many more of these we will see. I wonder when COs will
start dropping support for rotory phones into electronic switches? I
suspect it's coming now that tone dialing is "free" in California.
Maybe there will soon be a charge to allow rotory dialing in the
future with all rotory service moved to the old switches?
R. Kevin Oberman Lawrence Livermore National Laboratory
Internet: oberman@icdc.llnl.gov (415) 422-6955
Disclaimer: Don't take this too seriously. I just like to improve my typing
and probably don't really know anything useful about anything.Brian Kantor <brian@ucsd.edu> (06/02/91)
Ken Oberman wondered when COs would stop supporting pulse-dial (rotary) phones. Well, PBX's already have; the UCSD Ericsson MD-110 will not allow an extension phone to pulse-dial any number with a "1" (one) in it -- it interprets the single pulse as a switchhook flash and gives you a fresh dialtone. Of course, all the campus analog phones have touch-tone dials. We didn't discover the problem until people tried dialing the local Telenet node with their modems, some of which were older models that couldn't use touch-tone dialing. Last I heard, a couple of years ago, they'd have it fixed real soon. Hmm. It just occured to me: when they convert the student dorms to use the Ericsson phone system in a couple of years, will the students who own cheap plastic pulse-dial phones be able to dial 911? Brian
robert@uunet.uu.net> (06/04/91)
brian@ucsd.edu (Brian Kantor) writes: > Ken Oberman wondered when COs would stop supporting pulse-dial > (rotary) phones. Well, PBX's already have; the UCSD Ericsson MD-110 > will not allow an extension phone to pulse-dial any number with a "1" > (one) in it -- it interprets the single pulse as a switchhook flash and > gives you a fresh dialtone. Sounds like a misconfiguration or a bug in the Ericsson to me. The switch should be able to tell the difference between a 1 and a flash. Further, you imply that OTHER numbers can be pulse dialled, indicating that pulse dialing IS supported. I suspect that the person who configured your Ericsson figured that no pulse phones would be used, and they set the flash interval so small that it cannot be distinguished from a 1 (our old ITT 3100 PBX could be so configured). It makes flashing easier: you don't have that annoying problem of trying to flash but realizing that you haven't held the hook down long enough. Used to happen to me all the time until I convinced our ITT maintenance people to change the flash interval; it was ridiculously high. Never encountered these problems with our current AT&T System 25. The defaults are apparently just right. Robert Oliver Rabbit Software Corp. 215 993-1152 7 Great Valley Parkway East robert@hutch.Rabbit.COM Malvern, PA 19355 ...!uunet!cbmvax!hutch!robert
u1906ad@unx.ucc.okstate.edu (06/04/91)
brian@ucsd.edu (Brian Kantor) writes: > Ken Oberman wondered when COs would stop supporting pulse-dial > (rotary) phones. Well, PBX's already have; the UCSD Ericsson MD-110 > will not allow an extension phone to pulse-dial any number with a "1" > (one) in it -- it interprets the single pulse as a switchhook flash and > gives you a fresh dialtone. Oklahoma State University has had an Ericsson MD110 switch in use since Fall of 1988. It is a truly digital PBX with the vast majority of campus phones having A/D D/A converters in their bases. While I've been told that the signal on each wire pair is proprietary, it is pretty close to ISDN. Such indications as on-hook, off-hook, ring and caller id information are all just digital codes sent on the control channel. The situation that Bryan described regarding getting a fresh dial tone each time the hook was flashed sounds precisely like what happens when you flash the hook on an Ericsson digital phone. Ericssen also makes an analog line card which plugs into the MD110 switch so as to support such things as fax machines and the radio paging system operated by our physical plant. The analog line unit provides all of the standard telephone signals and will accept either pulse or tone dialing. The best way to tell what kind of Ericsson line one is on is to listen to the sound of the line as you dial a number. On a digital line, there is absolutely nothing heard between the dial tone and the first ring. Martin McCormick Amateur Radio WB5AGZ Oklahoma State University Computer Center Data Communication sGroup Stillwater, OK
sbrack@iuvax.cs.indiana.edu> (06/05/91)
cbmvax!.UUCP!robert@uunet.uu.net (Robert L. Oliver) writes: > It makes flashing easier: you don't have that annoying problem of > trying to flash but realizing that you haven't held the hook down long > enough. Used to happen to me all the time until I convinced our ITT > maintenance people to change the flash interval; it was ridiculously > high. On our NT SL100 PBX, the individual 2500 sets have a "tap" button, which, pressed once, sends a flash of the correct length. It seems to be some sort of capacitor arrangement, but since OSU is more paranoid than ATT about people opening up their phones, I haven't investigated. The tap button also houses the voicemail waiting lamp. This lamp also lights when ring current is applied to the instrument. What is the relation between the light and the ringer? Steven S. Brack | sbrack%bluemoon@nstar.rn.com Jacob E. Taylor Honors Tower | sbrack@bluemoon.uucp The Ohio State University | sbrack@nyx.cs.du.edu 50 Curl Drive | sbrack@isis.cs.du.edu Columbus, Ohio 43210-1112 USA | brack@ewf.eng.ohio-state.edu +1 614 293 7383 or 419 474 1010 | Steven.S.Brack@osu.edu
Julian Macassey <julian%bongo.UUCP@nosc.mil> (06/10/91)
In article <telecom11.433.8@eecs.nwu.edu> nstar!bluemoon!sbrack@ iuvax.cs.indiana.edu (Steven S. Brack) writes: X-Telecom-Digest: Volume 11, Issue 433, Message 8 of 13 > On our NT SL100 PBX, the individual 2500 sets have a "tap" button, > which, pressed once, sends a flash of the correct length. It seems to > be some sort of capacitor arrangement, but since OSU is more paranoid > than ATT about people opening up their phones, I haven't investigated. It is actually a Motorola IC. I have the schematic for these Comdial phones somewhere, buried with schematics for Yugoslavian phones etc. I can't find it now, but I did discover lots of neat stuff I haven't seen for a while. This circuit the "TAP telephone" was as I recall designed by Joe Flamini, a real telecom character. He is an MIT Phd, ex cop, bon vivant and comedian. Anyhow, the IC is a Dual Timer. One half sets up the flash button for a 600Ms break and the other half, which is across the hookswitch is set up for 1500 Ms. This is why when you try to flash the hookswitch on the TAP phone you hang the phone up. Comdial sold a ton of these things to ROLM who installed them as "ROLM Phones". They are still available as Comdial TAP phones from your local telco distributor. They come with or without the message waiting light. > The tap button also houses the voicemail waiting lamp. This lamp also > lights when ring current is applied to the instrument. What is the > relation between the light and the ringer? The "voicemail waiting lamp" is called the message waiting light. It is most often seen in hotel rooms. In hotels when they have a message for you, they turn on the light. This is done automatically with voicemail. The light is a neon with a 100K resistor in series. The voltage applied to the Tip and Ring to activate the light is usually 90V at 100Hz. This frequency is ignored by the frequency sensitive ringer that responds to 40 - 150V at 20 Hz. The neon is not frequency sensitive, so it flashes for message waiting or ring current. Julian Macassey, julian@bongo.info.com N6ARE@K6VE.#SOCAL.CA.USA.NA 742 1/2 North Hayworth Avenue Hollywood CA 90046-7142 voice (213) 653-4495
John Higdon <john@zygot.ati.com> (06/11/91)
Julian Macassey <julian@bongo.info.com> writes: > The voltage applied to the Tip and Ring to activate the light is > usually 90V at 100Hz. This frequency is ignored by the frequency > sensitive ringer that responds to 40 - 150V at 20 Hz. The neon is not > frequency sensitive, so it flashes for message waiting or ring > current. ITT uses a similar, but much simpler method of lighting the message waiting lamp. The System 3100 just sends 60 ipm pulses of 100VDC over the line. The direct current is completely ignored by the ringer, but lights the neon lamp. Unlike the 100Hz, there is no flow through any circuitry except for the neon lamp. In addition to being much more difficult to generate (than DC), some of the 100Hz will inevitably leak through the L/C bell network creating a bit of inefficiency. The DC supply is very simple and cheap. John Higdon | P. O. Box 7648 | +1 408 723 1395 john@zygot.ati.com | San Jose, CA 95150 | M o o !
Steve Forrette <forrette@cory.berkeley.edu> (06/13/91)
In article <telecom11.444.10@eecs.nwu.edu> Julian Macassey writes: > This circuit the "TAP telephone" was as I recall designed by > Joe Flamini, a real telecom character. He is an MIT Phd, ex cop, bon > vivant and comedian. Anyhow, the IC is a Dual Timer. One half sets up > the flash button for a 600Ms break and the other half, which is across > the hookswitch is set up for 1500 Ms. This is why when you try to ^^^^^^^ > flash the hookswitch on the TAP phone you hang the phone up. I think this is a really stupid feature. How do they expect you to dial the phone if the tone pad goes out? :-) Steve Forrette, forrette@cory.berkeley.edu [Moderator's Note: My office phone is like that. The switch always will disconnect; never flash. The TAP button flashes, but after a flash or two it seems to need to time out a few seconds before it is willing to flash again (it does nothing after the secod or third time it is flashed until a few seconds have elapsed.) Stupid. PAT]
Julian Macassey <julian%bongo.UUCP@nosc.mil> (06/14/91)
In article <telecom11.450.3@eecs.nwu.edu> John Higdon <john@zygot.ati. com> writes: X-Telecom-Digest: Volume 11, Issue 450, Message 3 of 11 > Julian Macassey <julian@bongo.info.com> writes: >> The voltage applied to the Tip and Ring to activate the light is >> usually 90V at 100Hz. This frequency is ignored by the frequency >> sensitive ringer that responds to 40 - 150V at 20 Hz. The neon is not >> frequency sensitive, so it flashes for message waiting or ring >> current. > ITT uses a similar, but much simpler method of lighting the message > waiting lamp. The System 3100 just sends 60 ipm pulses of 100VDC over > the line. The direct current is completely ignored by the ringer, but > lights the neon lamp. Unlike the 100Hz, there is no flow through any > circuitry except for the neon lamp. In addition to being much more > difficult to generate (than DC), some of the 100Hz will inevitably > leak through the L/C bell network creating a bit of inefficiency. The > DC supply is very simple and cheap. And of course what John doesn't mention is the best reason for using DC today is the dreaded Type B ringers. The telephone bell of old was frequency selective. 100 Hz would be out of the bandwidth of all types of mechanical ringer. Type B ringers are not the gong bells of old but the "crickets in heat" chirpers. According to FCC specs, a Type B ringer should respond from 15.3 to 68 Hz. In reality, these Type B ringers respond nicely to 100 Hz. This means in an office environemnt you can go nuts listening to a colleague's phone in the next pen (cubicle) chirp away every couple of seconds. DC from a good PBX will then save you the grief of a whole office sounding like a crickets orgy while the staff are out at a meeting and the voice mail is backing up. Julian Macassey, julian@bongo.info.com N6ARE@K6VE.#SOCAL.CA.USA.NA 742 1/2 North Hayworth Avenue Hollywood CA 90046-7142 voice (213) 653-4495