Cost effective way of converting a straight through cable into a null modem cable this null modem cable adapter features one db9 male and one db9 female connector a cost saving way to convert a straight through cable into a null modem cable the db9f null modem adapter is backed by lifetime warranty and free lifetime technical support the startechcom advantage a cost effective way of converting a straight through cable into a null modem cable easy to use and intall backed by startechcom3