All 1995 and earlier Porsche Carrera 993 models are "OBD I Certified".
Although the "late" 1995 models are equipped with the newer OBD II connectors, an OBD II code reader cannot be used to download MIL (Malfunction Indicator Light) trouble codes.
The "late" 1995 Porsche Carrera 993 uses a OBD II connector, although it is still an OBD I system.
OBD II J1962 Female Connector Pin-Out
The OBD II connector on the Equus 3030 Innova OBD II Diagnostic Code Reader shown for information purposes only.
From what I understand, it cannot be used to read the OBD I codes from a 1995 Porsche Carrera 993 with an OBD II connector.
OBD II J1962 Male Connector Pin-Out