davidsen%kbsvax.tcpip@GE-CRD.ARPA (08/25/86)
I would like to have a device to prevent outgoing long distance calls from my system. This will prevent abuse when rates are high. What I want is a box which will go between the modem and phone line, and monitor the outgoing tones. If the first tone is not a "1", the call is allowed, otherwise the line is disconnected. This sounds like an obvious item to have available, but I haven't seen it advertized, and the local phone stores don't seem to have it. Can anyone recommend such a device, or should I just build my own? -bill davidsen seismo!rochester!steinmetz!--\ / \ ihnp4! unirot ------------->---> crdos1!davidsen \ / chinet! ---------------------/ (davidsen@ge-crd.ARPA) "Stupidity, like virtue, is its own reward"
LENOIL@DEEP-THOUGHT.MIT.EDU (Robert Lenoil) (08/28/86)
Date: 25 Aug 86 11:25 EST From: davidsen%kbsvax.tcpip@ge-crd.arpa Subject: Toll Restrictor I would like to have a device to prevent outgoing long distance calls from my system. This will prevent abuse when rates are high. What I want is a box which will go between the modem and phone line, and monitor the outgoing tones. If the first tone is not a "1", the call is allowed, otherwise the line is disconnected. My fraternity bought just such a device (against my advice) from a electronics surplus place in Peabody, Mass. called BNR (I think). Although the device does prevent people from inadvertantly using your phone, it CANNOT stop someone who is intentionally trying to cheat you. The device we got was an in-line passive black box that disconnected the line if the first digit was one OR zero. It was reset by the presence of a dial tone. By eliminating zero, people couldn't even use the phone to make collect or credit card calls; they needed a Sprint account or something. This was no good, so I had to find a way around that. So...there is now a sign over that phone that reads: "To make a collect call: Depress the switchhook once rapidly, then press # + 02880 + area code + number." Telecom readers should understand what's going on here. Depressing the switchhook once "dials" a one (remember pulse-code dialing?). Pressing the # deactivates the toll restrictor, but is otherwise ignored by the phone company. After dialing the rest of the sequence, you have effectively dialed 10288 + 0 + area code + number, i.e. you have dialed an AT&T operator-assisted call. The above works, but anybody that understands the underlying reason can figure out how to dial a long distance number. Or, they can just ask the operator when she comes on to complete the call for them, because they were having trouble dialing or something. To thwart this, your device would also need to count pulses and disallow one or zero. But a person can usually call 555-1212 and have the information operator connect you to an operator, or... You can't win. The best solution is to keep the phone under lock and key.
S.PAE@DEEP-THOUGHT.MIT.EDU (Philip A. Earnhardt) (09/01/86)
> You can't win. The best solution is to keep the phone under lock and key.
True true. Even real phone systems have difficulty with this. Our company
uses MCI. We accesses it via the local 7-digit number, even though we've had
equal access for over 6 months. Besides the loss in quality and added delay
in connecting, the MCI number is often busy during the day (and our phone
system is too stupid to detect a busy signal)!
A while back, I discovered you could bypass the long-distance programming
by dialing 1 then #######. This gave me an outside line and dialed a 1 on
it. I then dial the area code and the number normally.