Mating Connectors - Seagate ST423451N Product Manual

Elite 23 Product Manual, Rev. A
A stub length of no more than 0.1 meter (0.33 foot) is allowed off the mainline interconnection with any con-
nected equipment. The stub length is measured from the transceiver to the connection to the mainline SCSI
bus.
Single-ended I/O pin assignments are shown in Tables 12 and 13.
9.6.3.2 Differential I/O circuits ("WD" models)
The maximum total cable length allowed with drives having differential I/O driver and receiver circuits is 25
meters (82 feet). Twisted-pair cable (either twisted-flat or discreet wire twisted pairs) should be used with differ-
ential I/O transceiver circuits. A stub length of no more than 0.2 meter (0.66 foot) is allowed off the mainline
interconnection with any connected equipment. The stub length is measured from the transceiver to the con-
nection to the mainline SCSI bus. The spacing of devices on the mainline SCSI bus should be at least three
times the stub length to avoid clustering (Refer to Annex C of X3T10/1071D). This restriction easily allows the
16 device IDs that the SCSI 16 bit wide bus can address. These values are from the ANSI SCSI-3 Fast-20
(also called Ultra SCSI) specification X3T10/1071D.
An ideal impedance match with cable terminators implies a cable characteristic impedance of 122 ohms. Differ-
ential I/O pin assignments are shown in Table 14.
9.6.4

Mating connectors

Part numbers for connectors that mate with the various Elite 23 I/O connectors are given in the sections follow-
ing.
9.6.4.1 Mating connectors for ST423451N model
Use a non-shielded 50-conductor cable connector consisting of two rows of 25 female contacts with adjacent
centers .100 inch apart.
Recommended mating flat cable connector part numbers are:
3M-3425-7000
3M-3425-7050
Berg-66900-290
3M-3425-6000
3M-3425-6050
Berg-66900-250
[1] See Figure 14.
The drive device connector is a non-shielded 50-conductor connector consisting of two rows of 25 male pins
with adjacent pins .100 inch apart. The connector is keyed (see Figure 15). Mating panel mount connector:
3M-CHE-2050-J01A10-KLE.
9.6.4.2 Mating connectors for ST423451W and ST423451WD models
Use a non-shielded 68-conductor cable connector consisting of two rows of 34 male contacts with adjacent
contacts 0.050 inch (1.27 mm) apart.
Recommended mating wide connector part numbers are:
Amp Model 786096-7
Amp Model 786090-7
Amp Model 749925-5
Amp Model 88-5870-294-5
Amp Model 1-480420-0
Berg 69307-012
[1] See Figure 14.
W/O Strain Relief, No Center Key
With Strain Relief, No Center Key
With Strain Relief, With Center Key
W/O Strain Relief, No Center Key
With Strain Relief, No Center Key
With Strain Relief, With Center Key
Female, 68-pin, panel mount
Female, 68-pin, cable mount
(.050 inch conductor centers, 28 or 30 AWG wire)
Use two, 34 conductor, .050 inch center flat cable with this con-
nector. This type connector can only be used on cable ends. [1]
W/O Strain Relief (.025 inch conductor centers, 30 AWG wire).
Use either on cable ends or in cable middle section for daisy-chain
installations. [1]
Power connector 4 circuit housing
12-position, 2 x 6, 2 mm receptacle housing
Closed-end
(for cable ends) [1]
Open-end
(in daisy-chain) [1]
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