Yes. The -2101 version provides two transponder antenna inputs or diversity. The diversity option allows selection of signal receptions from either a top or bottom mounted antenna based on the characteristics of the received signals. The -2001 version does not provide the diversity option. In the event that the diversity version -2101 must be used in place of the non-diversity version -2001, a simple input must be changed on connector J671A. Pin 89 of this connector identifies whether one or two antennas are used in the installation. Pin 89 is strapped to aircraft ground if only one antenna is used. Therefore, if installing a -2101 in a -2001 installation, no wiring changes are needed.