Note
QST, Feb 1972, p. 125.
QST, Jul 1972, p. 151.
QST, Jan 1973, p. 147.
The EK-404 was similar to the EK-402 keyer but lacked a programmable memory.
Standard features in the EK-404 include jam-proof dots, dashes and spaces; iambic or standard operation; dot memory; variable weighting; tune switch; built-in sidetone and speaker; a self-contained 115 VAC power supply and complete RF immunity.
Other features include a connection for 12 VDC mobile or portable operation, front panel control of sidetone pitch, a self-test mode, two sidetone outputs (Hi-Z, Lo-Z) and provision for either grid block and cathode keyed or solid state rigs.