miniSAS active cable keying

Elliott, Robert (Server Storage) Elliott at
Fri Jun 20 08:06:47 PDT 2008

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The receptacle key slots will mean:
a) no key slots: SAS-1 phy present, only <= 6 m passive cables supported
b) key slot 1: SAS-2 phy present, > 6 m passive cables supported
c) key slot 2: power provided.	A SAS-2 phy is probably present, but that's
A SAS-1.x receptacle includes no key slots.
A SAS-2.x receptacle not providing power will just include key slot 1.
A SAS-2.1 receptacle providing power will include both key slots 1 and 2.
The cable keys will mean:
a) none: <= 6 m passive cable
b) key 1: > 6 m passive cable, needs a SAS-2 phy
c) key 2: active cable, needs power
This ensures that:
1. short passive cables plug in everywhere
2. long passive cables only plug into receptacles with SAS-2 phys
3. active cables only plug into receptacles with power
It's up to the power supply logic behind a receptacle with key slot 2 to
determine if the cable is passive or active and only provide power to an
active cable.
(NOTE: the numbers of the key positions may change... e.g., these might be
slots "1" and "5" in the end)
Rob Elliott, HP Industry Standard Server Storage
From: owner-t10 at [mailto:owner-t10 at] On Behalf Of
Alvin.Cox at
Sent: Friday, June 20, 2008 9:04 AM
To: t10 at
Subject: miniSAS active cable keying
During our last SAS phy conference call, there were separate keys indicated
for active cables (see
08-257r0<;). I am
wondering what the implementation plan is. The keys provide no protection
|from plugging in a SAS 1.1 (legacy passive) cable and the phy's should work
with the SAS 2.0 10-meter passive version, so what is the advantage of adding
this key? I guess I am missing something in the planned implementation. Could
someone elaborate?
Alvin Cox
Seagate Technology, LLC
Office 405-381-8067
Cell 405-206-4809
E-Mail	alvin.cox at

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