Serial Storage Architecture
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Serial Storage Architecture [SSA] Bus defines the Physical layer interface. |
A character is defined as 10 bits. The Bit Encoding used is: Non Return
to Zero (NRZ) encoding for data communication on a
differential two wire bus. The use of NRZ encoding ensures compact
messages with a minimum number of transitions and high resilience to
external disturbance. Lines are terminated to 3.3 volts [2.97 minimum
/ 3.63 maximum] via a 75 ohm resistor.
The differential cable impedance is 150 ohms. The internal connector pin-out is shown below, other
connector pinouts are also defined. In addition a Power connector is defined.
Editor note; I have the impression this bus is OBSOLETE, being defined at TTL
levels. How ever, it may still reside on a few IBM main-frames.
It would be basically impossible for this standard to continue to compete with newer standards while relying on TTL signaling rates.
The pinout for a six pin internal port is shown below.
Pin |
|
---|---|
1 | LineOut+ |
2 | LineOut- |
3 | Chassis/Power GND |
4 | Logic GND |
5 | LineIn+ |
6 | LineIn+ |
ANSI; SSA Standards List
T10; SSA Documents, Specifications and Reference Info
It doesn't appear that this standard was every released by the IEEE.
Serial Storage Architecture - Physical Layer 1 (SSA-PH1) Rev 9c 1996
Serial Storage Architecture - Physical Layer 2 (SSA-PH2) Rev 5b 1997
Serial Storage Architecture - SCSI-3 Protocol (SSA-S3P) Rev 5b 1997
Serial Storage Architecture - Transport Layer 2 (SSA-TL2) Rev 5b 1997
It appears that this specification has not been re-affirmed yet.
So the release dates listed above for the standards appear to be current.
Which would imply that these standards describe an Out-dated or legacy Interface.
Normally when a specification is not re-affirmed means that interest in the standard has faded.
There are no companies that have been identified that produce components for the SSA interface.
However this site does include a generic listing of manufacturers;
Refer to Component Manufacturers, ordered by name; Basically a list of semiconductor vendors and other companies producing products
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