Oki OL1200 Service Manual page 214

4) Signal level
- LOW : 0 V to +0.8 V
- HIGH : +2.4 V to +5.0 V
5) Specifications
Item Description
Mode Compatibility mode, Nibble mode, ECP mode
Data bit length 8 bits: Compatibility mode, 4 bits: Nibble mode, 9 bits: ECP mode
Input prime Valid/Invalid
Receive buffer 8K, 20K, 50K, 100K, 1M Bytes