EQUIPMENT APPLICATION

T.O. 31W2-2GSC24-2

TM 11-5805-688-14-1

NAVELEX 0967-LP-545-3011

demultiplexer, and information describing the stuffing

5-27.

EQUIPMENT APPLICATION.

actions taken by the multiplexer in the processing of

Figure 5-3 depicts the use of several multiplexers in a

asynchronous channel inputs. Thus the total number of

typical system application. In the example shown,

ports, including overhead, used in any given

numerous lower rate channel inputs are multiplexed in

configuration may be expressed as N+1.

successive steps into a single high-speed output, which

5-24. The multiplexer's output rate (R ) is the product

is then applied to a communications link. The actual link

of the total number of ports used (N+1), and the port rate

may take any of several forms, including radio,

(Rp ), or Ro =(Rp ) (N+1).

microwave, or land line. The inputting of one multiplexer

with the output of another is commonly known as

5-25. Data applied to a multiplexer's input channels

tandeming, and the overall result is a hierarchy

may take several forms: digital data with associated

comprised of an output multiplexer being fed by the

timing, voice, and digital data without timing. Within

outputs of other multiplexers operating at successively

prescribed limits, inputs may be asynchronous with the

lower rates.

multiplexer's reference timing source and with each

other. Using a variety of input channel card types, all

5-28. Figure 5-3 illustrates the outputs from 20 third

data are converted to a digital form and are subsequently

level multiplexers No. 3-1 through 3-20 being applied to

processed as synchronous signals under control of the

two second level multiplexers No. 2-1 and 2-2. The

internally generated multiplexer clock.

outputs from these two multiplexers, plus two

independent digital inputs of 2.304 Mbps each, are the

5-26. Generally, a digital input channel rate (Rc) will be

inputs to first level multiplexer No. 1. The multiplexed

nominally equal to the product of port rate (Rp) and the

7.168 Mbs output from multiplexer No. 1 is routed to a

number of ports (K) assigned to that channel. In other

communications link for transmission to far-end

words, Rc = KRp. For cases where Rc ≠ KRp, the

demultiplexing equipments.

multiplexer is capable of performing a rate conversion

5-29. Multiplexers No. 3-1 through 3-5 each process a

process termed coarse rate conversion. This entails the

combination of voice and digital data inputs using a port

use of a KRp that is greater than the applied Rc, and a

rate (Rp ) of 9.6 kbps and a total (N+1) of 30 ports.

predetermined sequence of internal timing adjustments.

Output rate (Ro ) is 288 kbps (9.6 x 30 = 288). Using a

The degree of rate conversion that may be performed is

port rate of 2.4 kbps and a total of 20 ports each,

defined by the expression:

multiplexers No. 3-6 through 3-20 process a mix of

digital inputs and yield an output rate of 48 kbps. Note

0.96 > K (1 Rc)

that the data rate applied to channel 5 of multiplexers

KRp

No. 3-6 through 3-20 is 2.3 kbps. This rate takes the

form Rc< KR . Using the expression

The most important benefit resulting from the

multiplexer's coarse rate conversion capability is that it

0.96 > K (1 Rc)

enables simultaneous processing of digital channel input

KRp

rates from mixed rate families. A voice channel is

processed in the equipment, using a KRp of 19.2 kbps or

greater

Change 1 5-6