Hacking PC Pursuit (2600 Magazine, April, 1987)
PC Pursuit (PCP) is a service provided by Telenet (a division of U.S. Sprint)
for $25 a month for use after business hours weekdays, and all day on weekends.
You can use it during the business day for rates that will beat out
long-distance voice, but not by much. Some interesting hacks have presented
themselves in abusing, that is using, this service.
At the Telenet "@" prompt, a user types "CDIALXXX/12,USERNAME" where XXX is the
area code of the modem near your destination, and 12 is the speed (1200 Bits
Per Second (BPS)) you want to use at the destination modem. PCP provides you
with a Username when you sign up for the service. We ll come back to the data
After you enter that command line, PCP then asks for a password. You are
provided with a password by PCP, and cannot change it. You can have them change
it, and send you the new password in the mail. After you type in your password,
you are either connected to a "Hayes-compatible" modem in the distant city, or
you are given the message "XXX BUSY," where XXX is once again the destination
area code. As more people try to use the limited number of modems PCP has in
what it thinks are major hotbeds of BBS action (Seattle?), more and more "busy
signals" are encountered on the Net.
When placing your call to the remote modem, the number after the slash tells
Telenet what speed to set up the connection at. Besides "12," "3" is also valid
(for 300 BPS). However, "12" is valid even if you are calling into Telenet at
300 BPS, such as from a Tandy Model-100 (don't laugh; I'm preparing this
article on a Model-100). Telenet is known as a "value added" network, and this
is where it provides its "value added" services. The modem at the other end
doesn't know if you are at 300, or 110, or even a synchronous mainframe with
Ebenezer Scrooge for a system manager (watch for more "stingy manager" types to
take advantage of these low rates).
It must be said, however, that if you download huge ASCII files via a 1200/300
connection, you may overload the network buffer with your transfer. If that
happens, you will get an error message of "BUFFER OVERLOAD - SOME DATA HAS BEEN
LOST." The thing to do is to send a Ctrl+S once in a while. The stuff will keep
coming at you for a while, because of the speed differential, and when the
network buffer finally empties, the transmission will stop. Naturally, a Ctrl+Q
will start you up again, if your host hasn't logged you off for inactivity in
the meantime. Protocol transfers only transfer 128 or so bytes at a time, and
will be slow, but will not overflow buffers.
PCP says that the first thing you should do when you hit the modem is type "ATZ"
to reset the modem. On the contrary. The first thing to do when Telenet reports
"CONNECTED" is to type "A/," the Hayes command to repeat last command received.
Most people will let their host hang up the connection, and then just hang up
on PCP. In such a case, the last command given the modem was an "ATDT" command
to place the call. The PCP modems are funny, though. If they have received an
"ATZ," and therefore have no command in the command buffer, they will not echo a
"/" character. This tells you to immediately go about your own business. When
you've finished perusing the computer your PCP predecessor left in the modem,
dial up your own machine.
When you re through with your computer, either it will hang up on you, or you
must tell the modem to hang up on it. If you have to hang up, type "+++." You
have just sent the "Hayes wake-up" command to two modems. Yours (assuming you
have a Hayes compatible yourself), and the remote PCP modem in the distant
city. Type "ATS2=65" followed by a return. You've just told your modem that it
should only wake up when you type "AAA" (three capital A's) instead of "+++."
Now type "ATO" to get back on line with PCP.
When we last left our remote modem, it was waiting for your command after
receiving "+++" from you. Type "ATH" to hang it up. If you have other machines
to dial in the remote city you've dialed, keep dialing (send the next "ATDT"
command). If you ve called area code 212 and want to reach a Brooklyn BBS, type
"ATDT17185393560," since the 718 area code is within the New York City LATA
(Local Access and Transport Area). The same for calling Burbank (818) out of
the LA area code, 213.
One friend of mine recently had the mistaken impression that PCP no longer went
to the 415 area code. Sure, it's busy a lot, but that area's a busy hotbed of
activity. To check out his claim, we got up on PCP and got busy message after
busy message at 415/12. We decided to try 415/3 for a 300 BPS modem, and sure
enough, we got one. It was slow as expletive, but we got there. Then our BBS in
Berkeley was busy, and we were back to square one.
After you've had your fun, remember! Now is the time to hit "ATZ," before you
hang up on the remote modem. When you're through with all the calls you want to
make in the city you've reached, you should type the "ATZ" to your remote
modem, and get back to Telenet to set you up with a call to a modem in another
city. The best way is to type "@" followed by a carriage return. This will wake
up Telenet, and give you an "@" prompt. Type "D" for Disconnect, and it will
drop your connection to the modem in the city you had called. At the next "@"
prompt, type "C DIALYYY/12,USERNAME" (YYY being the new area code), and begin
the whole process again.
Are you in an area with multiple calling rates (such as New York City), with
toll rates within the LATA? "Some people' are known to use PCP within their own
area code (my modest nature and my constitutional rights preclude me saying any
more). A caller in Manhattan can get his or her 25 bucks back quickly just by
using PCP to call up BBS's on Long Island. Westchester also has some neat
boards in 914 that are easy to hit this way.
So there you have it. Remember to "ATZ" the modem before you leave it. While
the next caller can't find out what number is in the buffer, they can certainly
get at least one call into whatever you've just hung up on. I ve even wound up
on Teleconnect Magazine s BBS on an "A/," much to everyone's surprise.
Some of you may recall back in the early days, PC Pursuit had a rather unique
system. You dialed a special number and entered all of your personal
information ID code, password, and number you wanted to reach. PC Pursuit would
then hang up and call you back at a predetermined number.
That system was limiting because you couldn t use it from more than one
location. Some hackers claim to have gotten into their outgoing lines as they
were dialing out and gained access in that way.
The way the system is set up now is almost acceptable. PC Pursuit must set up
many more modems in many more cities before we sign up again.
It s also possible the way they have it working to tie up the entire system
single-handedly. For example, from the Telenet number in New York, we could
call the Telenet number in Seattle, enter our ID over there, call the Telenet
number in Dallas, and set up a huge nationwide circle.
We saw this done once and the delay between the time a character was typed and
the time it showed up on the screen was nearly 30 seconds! Needless to say,
there were many busy signals that day.
By Cheshire Catalyst