CHANNEL AND PORT RELATIONSHIPS.

T.O. 31W2-2GSC24-2

TM 11-5805-688-14-1

NAVELEX 0967-LP-545-3010

3-9. Figure 3-2 depicts the multiplexer set in typical

3-13. When a port assigned to a given channel occurs,

simplex system configurations.

In simplex system

a single bit of the channel data passes to the

applications, the independence of multiplexer and

multiplexer's output. Therefore, the rate at which the

demultiplexer functions enables one function, or portions

porting occurs must equal the channel's input data rate

thereof, to operate while the other function remains

(Rc). However, since the multiplexer set must be

unused. As shown in configuration A of figure 3-2, the

capable of simultaneously accepting channel inputs of

multiplexer portion of multiplexer set No. 1 combines

different rates, multiple ports may be assigned to a single

inputs a, b, and c for transmission to a farend

channel. The number of ports thus assigned to a given

demultiplexer that is a part of multiplexer set No. 2. In

channel may vary up to a maximum of 25, and is termed

such an application, the near-end demultiplexer and far-

K. The assignment of more than one port to a given

end multiplexer functions are not used.

channel is termed port strapping. The first port assigned

to a channel is known as the active port, and subsequent

3-10. Configuration B of figure 3-2 depicts another type

ports assigned to that channel are known as strapped

of simplex application, which is sometimes referred to as

ports. The product of the rate that each port is sampled,

a broadcast arrangement. In this application, data from

known as port rate (Rp), and the total number of ports

a near-end multiplexer are transmitted to several farend

(K) assigned to a channel must be equal to or greater

demultiplexers. Each demultiplexer is configured to

than the channel's input data rate (Rc), or KRp > Rc. In a

output one (or more) of the channels applied to the

given multiplexer configuration, the total number of ports

transmitting multiplexer. In such an arrangement, the

assigned to the multiplexer's channels is known as N,

near-end demultiplexer, the far-end multiplexers, and

and must be an integer between 15 and 31.

portions of the farend demultiplexers are not used.

3-14. Regardless of configuration, a single port within

3-11. CHANNEL AND PORT RELATIONSHIPS.

the multiplexer is automatically reserved for conveying

overhead data generated within the multiplexer into the

3-12. Data applied to the multiplexer's channel inputs

multiplexer's output data stream. Thus, in any given

are converted, when necessary, into a prescribed digital

multiplexer configuration, the total quantity of ports used

form and are held in buffer storage until they are

for processing channel and overhead data is N + 1, and

synchronously inserted into the multiplexer's serial output

is between 16 and 32. The multiplexer's output data

data stream. Since data from multiple channels must

rate, termed Ro, is simply the product of port rate (Rp)

enter this stream, they are inserted at a predetermined

time in an established channel sampling sequence. The

and the total quantity (N + 1) of ports used, or Ro = Rp

interval of time during which data from a given channel

(N + 1).

are allowed to enter the multiplexer's output stream is

termed a port. Thus, in a given multiplexer configuration,

3-15. The port assignments in a receiving demultiplexer

a port is permanently assigned to a particular channel

must exactly match those used in the transmitting

and will convey that channel's data into the multiplexer's

multiplexer.

This enables the demultiplexer to

output when the port occurs.

disassemble its serial input data stream into individual

channel outputs matching the multiplexer's inputs. In

applications where several

Change 2 3-3