I've updated my ART-13 Keying page. Includes info on the main R/T
relay, the antenna relay, as well as screen and oscillator keying.
Two mosfet circuits for solid state keying are published. The solid
state keying results in very quite CW transmitter (reduces the relay
CLACK CLACK CLACK) and also helps reduce relay maintenance. The
mosfet keying circuits do not effect phone ops.
K4CHE

http://k4che.com/ART-13%20Keyer/ART-13%20Keyer.htm