700-701-100-02

Functional Description

 

 

G.704 Framing and Rate Selectable HDSL

Time slots 0 and 16 are always transported in accordance with the G.704 framing standard. Although not used by G.703 to transport data, the rate-selectable HDSL interface treats time slots 0 and 16 as a 128 kbps increase in the HDSL payload rate. For example, when 4 time slots are selected (256 kbps), time slots 0 and 16 are transported along with the selected time slots, 1 though 4. This results in an HDSL payload rate of 384 kbps (that is, 256 kbps plus the 128 kbps added by time slots 0 and 16). Table 9 lists several examples of selected and actual HDSL payload rates.

In structured mode, time slots 0 and 16 do not contain data and are transparent to the G.703 input. The transmitted G.703 data arrives at both the customer and network DTE at the selected HDSL payload rate. This is illustrated in Figure 6 on page 14.

Table 9. Examples of Selected and Actual HDSL Payload Rates

Selected HDSL Payload

 

 

 

Actual HDSL Payload

Rate (kbps) / Number of

G.703 Time Slots Transported

Time Slots

Rate (kbps)

 

 

 

 

 

64

/ 1

1 (plus 0 and 16)

 

256

 

 

 

 

128

/ 2

1 and 2 (plus 0 and16)

256

 

 

 

 

192

/ 3

1 through 3 (plus 0 and16)

320

 

 

 

 

256

/ 4

1 through 4 (plus 0 and16)

384

 

 

 

 

384

/ 6

1 through 6 (plus 0 and16)

512

 

 

 

 

512

/ 8

1 through 8 (plus 0 and16)

640

 

 

 

 

 

640

/ 10

1 through 10 (plus

0 and16)

768

 

 

 

 

 

 

768

/ 12

1 through 12

(plus

0 and16)

896

 

 

 

 

 

 

896

/ 14

1 through 14

(plus

0 and16)

1024

 

 

 

 

1024

/ 16

1 through 15 and 17 (plus 0 and16)

1152

 

 

 

 

1152

/ 18

1 through 15, 17 through 19 (plus 0 and16)

1280

 

 

 

 

1536

/ 24

1 through 15, 17 through 25 (plus 0 and 16)

1664

 

 

 

 

1920

/ 30

1 through 15, 17 through 31 (plus 0 and 16)

2048

 

 

 

 

 

 

1984

/ 31

1 through 31

(plus

0)

2048

 

 

 

 

 

 

2048

/ 32

0 through 31

(a)

 

2048

 

 

 

 

 

 

 

(a) The line and desktop units operate in the unstructured mode when 32 time slots are selected.

HOT SWAPPING

UTUs can be inserted and removed from any compatible shelf or enclosure with the power turned on. This will not cause damage to the units nor will it cause interference to any other HDSL circuits that are operating within the same shelf or enclosure.

UTU-701 and ETU-751 List 1

August 9, 2002

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