CSvax:Pucc-H:ac4@pur-ee.UUCP (09/24/83)
I was recently reading the manual for the Hayes Smartmodem 1200B and found the following remarks on FCC registration: "The Smartmodem 1200B is registered with the FCC which places three restrictions on its use: * The Smartmodem cannot be connected to a party line or pay telephone. * The telephone company must be notified that an FCC registered device is being installed. * Hayes .... must make and necessary repairs ... I thought I read that notification of the local telephone company was no longer required after 1 Jan 83 ... Anyone know for sure? How about the party line restriction ... The rationale is obvious (i.e. you must get off the line in an emergency, etc.) but the question is whether this is really illegal on the federal level? We have had people using their home computers from the dorm rooms - all of which have party lines. The local telephone people have said it is probably OK since anyone can go across the hall and use another phone in an emergency. Tom Putnam ...!pur-ee!pucc-h:ac4
dwl@hou5e.UUCP (09/26/83)
The reason the FCC does not let you connect customer-provided equipment (voice or data) to 2 party lines is that the central office equipment on such lines relies upon some jumper wiring in the individual telephone set for originating party identification. If your equipment fails to identify which party it is, your outgoing calls may be billed to the other party -- toll fraud! A further complication is that for incoming calls on two-party lines, your bell (or ring detector, if it's a modem) must be able to determine which party is receiving a call. If your does not, you'll auto-answer a call intended for the other party. The prohibition regarding pay phone lines is similar: If your modem or customer-provided phone does not collect a dime (or whatever the initial period charge is in your area) then you are stealing something! -Dave Levenson -ATT-ISL, Holmdel
jhh@ihldt.UUCP (John Haller) (09/26/83)
The reason that nothing besides TelCo installed phones are not permitted on party lines is not because of getting off the line for emergencies, it is for both receiving calls and determining the originating party for billable calls. I do not know all the specifics of how its done, and I probably couldn't say if I did, but it works something like this: There is a special form of ringing for party lines, depending on which of the parties is being called. If the modem was in auto-answer mode, it would pick up both your calls and those of your party. Since only the TelCo knows how it hooked up the phone, you couldn't tell your modem which ones to pick up. The other problem is that the TelCo cannot determine which of the parties placed a (long distance) call when it is dialed by other than the TelCo installed phone. The above seem to eliminate all auto-answer modems, plus all `keyboard dial' modems. I don't know if any direct connect modems would meet FCC regulations for party lines. John Haller
dmmartindale@watcgl.UUCP (Dave Martindale) (09/29/83)
I read somewhere that the ringer on two-party-line phones is connected between one of tip or ring and ground rather than between tip and ring. Thus an originate-only modem which does not autodial might work correctly if you actually dialed the call with your phone. Can anyone confirm or refute this?
tll@druxu.UUCP (10/01/83)
There are several arrangements for connecting the ringers on party lines. One technique is to connect the ringers between tip-and-ground and ring-and-ground. This only selects between two ringers. Another arrangement is to accompany ringing voltage (normally 90VAC at 20Hz) with a DC voltage of one or the other polarity to select ringers. This again limits you to distinguishing two parties. Another technique is to tune the ringers to different frequencies, so you can select them by frequency. I'm not sure how many different ringers you can select using this method. A fourth arrangement is to ring with different patterns, so the humans decide from the ring if the call is for them (or if they want to listen in). Some of these techniques can be combined to select a larger number of ringers. Aside from ringing the right phone, there is the issue of billing the right party for outgoing calls. I'm less familiar with the techniques used for this, but I'm sure there is similar variety. The point is that there are MANY different arrangements used on party lines, and almost anything you can think of will screw up at least one of them. That's why nobody sells over-the-counter phone equipment for party lines. You don't have much choice except to go through the phone company. Tom Laidig ...!ihnp4!druxu!tll
dya@unc-c.UUCP (10/02/83)
References: watcgl.894
I always thought that the ringer on two party line phones were frequency
selective ?? Does anyone know the origin of this ?
dyajsol@bbncca.ARPA (Jon Solomon ) (11/09/83)
The reason you can't connect to party lines is because most party lines don't have "standard" RJ11C jack configurations, and also sometimes need more than the standard two wires that normal lines use. A party line makes use of sleeve and ground, especially to determine whose phone needs to be rung. In most cases, if you use a party line phone, it won't be on a RJ11C. If it is, and you have standard 2-wire service (with the party line stuff resolved at the pole, for example), then you are lucky; but like most laws, it applies to everybody, and not everybody is as lucky. That's the same logic which tells AT&T that it can't charge less for credit cards you enter yourself than when an operator does it (majority of areas don't have this feature). I hope I don't have to explain why you can't connect it to a pay telephone line. I remember connecting an *acoustical* modem to a pay telephone, but that's another story. --JSol