Cisco 6200 User Manual page 10

1
Hardware Description
Figure 1-5
The optical interface performs the optical-to-electrical and electrical-to-optical conversions. Its
other tasks include clock recovery, overhead processing, cell delineation, and diagnostic information
retrieval.
The upstream data transfer unit receives data via a 16-bit parallel input from the internal bus on the
node's backplane. ATM cells are received from an SLC channel only after that channel has won
access to the upstream data bus from the other contending line channels. The upstream data transfer
unit monitors the contention bus to direct inbound data to the optical interface.
The downstream data transfer unit inserts data onto the bus. This circuit inserts idle cells when a full
data cell is not yet ready for transmission.
1.3.2 NTC OC-3: Physical Description
The NTC resides in slot 1 (the left-most slot as you face the front of the chassis). Each OC-3 NTC
faceplate is marked NTC OC3-SM (single-mode) or NTC OC3-MM (multimode). The faceplate
(see Figure 1-6) includes the fixtures discussed in the following paragraphs.
OC-3c Trunk Port
The dual SC connectors (one for transmitting, one for receiving) for the Cisco 6200 network trunk
port are recessed into the OC-3 NTC faceplate to prevent the cables from protruding too far outside
the faceplate.
Warning
Warning
connected, avoid exposure to laser radiation and do not stare into open apertures.
1-10 Cisco 6200 User Guide
NTC OC-3 Application
Downstream
transfer
Optical
ATM on
interface
OC-3c
Upstream
data
transfer
Class 1 laser product.
Because invisible laser radiation may be emitted from the aperture of the port when no cable is
NTC
data
78-5296-02
Cisco
6200
Line
module
10/02/98