TY - RPRT TI - Federal Information Processing Standards Publication: 12,000 and 14,400 bits per second four-wire duplex modems for data communications use on telephone-type circuits PY - 1992 PB - National Institute of Standards and Technology CY - Gaithersburg, MD SN - NIST FIPS 168 DO - 10.6028/NIST.FIPS.168 ER -