|4||Note that lines 4 & 5 are tied together at the computer end.|
|6||Note that lines 6 & 20 are tied together at the computer end.|
This is a variety of NULL modem cable. The 4/5 & 6/20 jumpers enable the PC to 'think' that a device is attached and ready to transmit. From the schematic it's clear that the Macbeth does all handshaking through software rather than through any combination of control lines. Below is equivalent wiring for a DB9:
|4||Note that lines 4 & 6 are tied together at the computer end.|
|7||Note that lines 7 & 8 are tied together at the computer end.|
Again this is a NULL modem variation where the PC provides its own hardware handshake signal. One caveat, the Macbeth 2020 (Color-Eye) may have ICS EEPROM installed. If this is the case X-Rite's software will NOT communicate with the unit. Per Ray Carmondy, it may be possible to order a standard EEPROM from Macbeth to replace the ICS specific chip.