B. Making Your Own CableB-2 UniSite-xpi User ManualMaking Your Own CableThe programmer receives commands and sends responses through anRS-232C port using a 25-pin D connector in two possible configurations:either DTE or DCE. The connections are shown in Figure B-B-1.Figure B-1Pin Designations for RS-232C Serial Port Connection8232076459-1921-251123456789DCDDATADATADTRSIGNAL GNDDSRRTS (HELD HIGH)CTSDCDTRANSMITRECEIVEDTRGNDDSRRTSCTSRECEIVETRANSMIT25 PINUNISITE (DCE)9 PINTERMINAL (DTE)NCNCNCNC123456789-192021-251234567820PROTECTIVE GNDDATADATARTS (HELD HIGH)CTSDSRSIGNAL GNDDCD (HELD HIGH)DTRNCNCGNDTRANSMITRECEIVERTSCTSDSRGNDDCDDTRRECEIVETRANSMIT25 PINUNISITE (DCE)25 PINTERMINAL (DTE)0362-4The minimum hookup includes Pins 2, 3, and 7.Pins 1 and 7 are tied together.123456789-192021-251234567820PROTECTIVE GNDDATADATARTS (HELD HIGH)CTSDSRSIGNAL GNDDCDDTRNCGNDRECEIVETRANSMITRTSCTSDSRGNDDCDDTRTRANSMITRECEIVE25 PINUNISITE (DTE)25 PINMODEM (DCE)NC8232076459-1921-251123456789DCDDATADATADTRSIGNAL GNDDSRRTS (HELD HIGH)CTSDCDRECEIVETRANSMITDTRGNDDSRRTSCTSTRANSMITRECEIVE25 PINUNISITE (DTE)9 PINMODEM (DCE)NCNCNCNCIN OUT
