TruePulse is looking to purchase NT7E05JB and NT7E05JC for the Nortel S/DMS TransportNode OC-3/OC-12 system.  It is possible that you may be familiar with these as Ciena NT7E05JB and the Ciena NT7E05JC.

TruePulse is currently looking to buy:

  • NT7E05JB, HECI code SNI2DA81AB, is an OC-12 IR 1310nm VTM optical interface circuit pack (connectorless)
  • NT7E05JC, HECI code SNI2AA81AA, is an OC-12 LR 1310nm VTM optical interface circuit pack (connectorless)

The OC-12 VTM circuit pack is used in the VTM ring ADM. For this application, two units are required. One unit handles the working and protection channels traveling in the east-to-west direction, and the other unit handles the working and protection channels traveling in the west-to-east direction.

The OC-12 VTM circuit pack provides

•interface to the OC-12 signal

•bandwidth management at the STS-1 level and at the VT1.5 level

•timing to maintain the synchronization of the network element

Timing

When equipped in the primary transport slots, the OC-12 VTM circuit packs are responsible for generating shelf timing. Each OC-12 VTM circuit pack has a system clock generator that generates a 52 MHz clock, a 38 MHz clock, and a 2 kHz clock. The clocks are distributed to the tributary interfaces in the TBM shelf.

The master OC-12 VTM circuit pack locks to the selected timing reference for the shelf, and the slave unit locks to a timing reference provided by the master unit. The master OC-12 VTM circuit pack can lock its system clock generator to any of the following timing references:

• a 51.84 MHz timing reference supplied by an ESI card in the shelf

• timing signals in the received OC-12 signal

• a received OC-12 or STS-12 signal from the secondary transport slots

In the event that the timing reference is lost, the OC-12 VTM circuit pack provides a holdover capability that can maintain the frequency to within 4.6 ppm for a period of 24 hours (but ESI will overrule if equipped). The OC-12 VTM circuit pack can free-run with a frequency accuracy of ±20 ppm.

The OC-12 VTM circuit packs provide access to the synchronization-status messages contained in bits five to eight of the S1 byte of the SONET line overhead. In a VTM ring, each network element encodes the synchronization status message in the outgoing SONET signal. The message informs the adjacent network element of the quality level of the timing of the SONET signal. If a network element must choose a new timing source, because the active timing source has degraded or has been lost, then it chooses the highest-quality timing source available.

We are also interested in other Nortel S/DMS TransportNode OC-3/OC-12 cards that you may have available.  Furthermore, we are interested boards for other Nortel platforms too, including the  S/DMS TransportNode OC-48 and the OME6500.  Please contact us to let us know what you may have available.

Nortel NT7E02LC