Priority Quality Level (PQL)


Symmetricom, Inc. has defined Priority Quality Level (PQL) values to allow translation of SSM values for mixed carrier (DS1 and E1) environments. The SSM to PQL translation is performed by the input when SSM signals are received. The PQL to SSM translation is performed by the DS1/E1 output when SSMs are generated.

PQLs allow the system to compare and rate the signal quality from different sources, and provide an effective way to communicate the quality of output signals. Corresponding PQL numbers and SSM values for DS1 and E1 are listed below.

PQL #

DS1 SSM

DS1 Text Description

E1 SSM

E1 Text Description

1

 0x08

 

 0x00

 

2

 0x04

PRS

 0x02

 

3

 0x04

 

 0x02

PRC/G.811

4

 0x08

STU

 0x00

STU

5

 0x0C

St2

 0x04

Type II

6

 0x0C

Type I

 0x04

Type I

7

 0x78

Type V

 0x04

G.812 Transit

8

 0x7C

St3E

 0x08

Type III

9

 0x10

Type VI

 0x08

G.812 Local

10

 0x10

St3

 0x0B

Type IV

11

 0x22

 

 0x0B

G.813 Opt1

12

 0x22

SMC

 0x0F

G.813 Opt2

13

 0x28

St4

 0x0F

 

14

 0x40

Reserved

 0x0F

 

15

 0x30

DUS

 0x0F

DUS

16

 0x40

 

 0x0F