© 2001, Myricom, Inc.
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Revision: 27 August 2001
Serial
links carry Myrinet packet data at a 2+2 Gb/s data rate on industry-standard HSSDC
(High-Speed Serial Data Connector) cables up to 10m in length. These shielded cables are
certified in several small configurations to Class A limits for the emission of EMI
1
. Myricom
supplies HSSDC cables from manufacturers whose cables we have qualified through extensive
testing. Not all HSSDC cables will function properly as Myrinet Serial cables.
The HSSDC cable-end connector snaps into a Serial port. Please observe the locking tab on the
cable-end connector:
In order to remove a cable, it is very important to depress the locking tab. Otherwise, the port
connector will be damaged.
SAN
(System Area Network) links are carried on unshielded “microstrip” ribbon cables up to
3m in length. In fact, a single cable carries two links, designated as
the “A” and “B” links, and the same cables are used for two different
Myrinet PHYs, SAN-1280 (1.28+1.28 Gb/s) and SAN-2000 (2.0+2.0
Gb/s). As you can see from the photo to the left, SAN cable-end
connectors include a locking mechanism. These locking springs
should both be depressed when inserting and when removing a SAN
cable-end connector.
SAN links are for “in-cabinet” applications only.
Switch configurations with any SAN line
cards (M3-SW16-8M or M3-SW16-4DM) exceed Class A limits for EMI, and should be used
only within a shielding enclosure. Also, it is best to restrict the use of SAN cables to within an
enclosure because they will withstand only moderate physical abuse.
LAN
(Local Area Network) links are a legacy PHY of Myrinet-1280. These multi-conductor,
shielded cables are rugged, and are terminated with DB-37 connectors (similar to SCSI DB-25
connectors, but larger). LAN cables and components are certified for EMI to Class A limits.
The only installation precaution is to be sure that the locking screws are screwed down
tightly
.
1
Tests of large configurations of Myrinet switches show that products such as the M3-E128 with all Serial ports
show very small margins relative to Class A limits in the 3–6 GHz range. These tests show that this EMI is due to
characteristics of the HSSDC connectors. Myricom is continuing engineering efforts to reduce the EMI emissions,
including using a different type of HSSDC connector in the most recent production products.
Locking
Tab
