Datasheet

40G Cabling Technical Q&A Document
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Q. What is the specification for the QSFP+ to QSFP+ cable?
A regular MTP-12 to MTP-12 cable as shown below is also used for direct 40G to 40G connections.
At the MTP ends there are 12 fibers (an MTP-12), and two guide pins (or sockets), which can be
seen in the photograph below.
To directly connect two QSFP+ ports, the 12-fiber assembly uses a pinless MTP connector on both
ends to interface with the QSFP+ ports on the switch (the pins are in the transceiver port). The
example diagram below shows how fiber 1 (blue fiber) is in position 1 on one end and in position 12
on the other end. This positioning is required for transmit and receive to connect. The part numbers
for this configuration are in the table below.
Corning Part Number
Description
J757512QE8-NB010F
12-fiber jumper; MTP (F) to MTP (F); Type- B Polarity; OM4 50/125;
overall length of 10 ft
J757512QE8-NB020F
12-fiber jumper; MTP (F) to MTP (F); Type- B Polarity; OM4 50/125;
overall length of 20 ft
J757512QE8-NB030F
12-fiber jumper; MTP (F) to MTP (F); Type- B Polarity; OM4 50/125;
overall length of 30 ft
The application for the above MTP-MTP jumper cable is to directly connect a QSFP+ port to
QSFP+ port. For most Data Center applications, the use of structure cabling is employed via MTP-
MTP trunks and the use of patch panels. For more detailed guidance on the applicable MTP
jumper configuration and part number needed, please refer to the following document for more
detailed information. Additional detail is included in the below document on solutions that enable
increased fiber utilization:
http://csmedia.corning.com/CableSystems//Resource_Documents/application_engineering_notes_rl
/AEN151.pdf
Rx1
Rx2
Rx3
Rx4
x
x
x
x
Tx4
Tx3
Tx2
Tx1
QSFP
Accepts+
Key+Up
Tx1
Tx2
Tx3
Tx4
x
x
x
x
Rx4
Rx3
Rx2
Rx1
QSFP
Accepts+
Key+Up
Key
Up
12
1
Key
Up
12
1