We recently purchased and installed the Radio Shack 49-1000. Our door and motion sensors are holdovers from the previous DS7000 system. We have 3 remotes: 2 Keychain Remotes (One KR31A and One KR10A), and 1 larger remote.
Pressing and holding a button on either of the keychain remotes did not cause the system to 'not alarm'. Actually, it appears the keychain remotes transmit a single RF burst signal; even if a key is constantly depressed. Even while holding the button down, and opening a window, the alarm still activated.
However, the larger remote did jam the sensor signals and seems to transmit a constant RF signal as indicated by the remote LED constantly flashing. Sensors were ineffective.
As someone mentioned in an earlier post, if a burglar is semi-sophisticated enough to bring a remote (or any RF transmitter operating on the proper frequency) and jam our system; then they will get in no matter what you do.
Just wanted to pass on our experience with the remotes and system jamming.
v/r
Bob P