Fujitsu MCM3130SS, MCP3064SS, MCM3064SS, MCP3130SS manual Interface cable requirements

7.3 Physical Requirements

7.3.2 Interface cable

For the interface cable, a 25-pair, twisted-pair cable that satisfies the requirements listed in Table 7.2 should be used.

Table 7.2 Interface cable requirements

Item
Conductor size	28 AWG or bigger
Characteristic impedance	Ω	Ω
	100	to 132

In the 25-pair twisted cable, pins n and n + 1 (where n is odd) on the interface connector must be connected to a pair. Cables having the same characteristic impedance must be used in the same SCSI bus to reduce signal reflection and maintain transmission characteristics.

The maximum length of the interface cable is 6 m. But the cable length is restricted according to the synchronized transfer speed. When an SCSI device is connected to the interface cable except at one of the ends, the connection to the SCSI connector must be at a cable branchpoint. When an SCSI device is connected to an end of the SCSI bus, there must not be any cable wiring after the SCSI device unless the cable has a terminating resistor. (See Figure 7.7.)

C156-E228-02EN 7-9