Specifications

BASIC Stamp II Application Notes
Page 346 • BASIC Stamp Programming Manual 1.8 • Parallax, Inc.
From a more technical standpoint, X-10 signals are digital codes im-
posed on a 120-kHz carrier that is transmitted during zero crossings of
the AC line. To send X-10 commands, a controller must synchronize to
the AC line frequency with 50-microsecond precision, and transmit an
11-bit code sequence representing the button pressed.
A company named X-10 owns a patent on this system. To encourage
others to use their technology without infringing their patent, X-10 sells
a pair of modules that provide a relatively simple, safe, UL- and CSA-
approved interface with the AC power line. These interfaces are the PL-
513 and TW-523. The PL-513 is a transmit-only unit; the TW-523 can be
used to transmit and receive X-10 codes. The Stamp II presently
supports only transmission of X-10 codes, but either of the interfaces
may be used. The figure shows how they connect to the Stamp II.
A word of caution: The PL-513 or TW-523 provide a safe, opto-isolated
interface through their four-pin modular connector. However, they
derive power directly from the AC power line. Never open the cases of
these devices to make connections or measurements. You’ll be exposing
yourself to a severe—even deadly—shock hazard.
That said, connecting to the PL-513 or TW-523 is easy. They use a
standard four-conductor modular phone base (not handset) connector.
Cutting a 12-foot phone cord in half yields two 6-foot X-10 cables. The
1234
TW523 or PL513
powerline
interface
BS2
+5
10k
pin 0
pin 1
4-conductor phone base
(not handset) cable
1
2
3
4
Schematic to accompany X 10_ DEMO . BS 2
1: X-10 Control