4. Configuring the Unit Using the Internal Switches4-4 December 2001 7900-A2-GB21-20Model 7974 Switchpack DefinitionsFor Switchpack S4 definitions, refer to Table 4-1, Switchpack S4 Definitions(Model 7974).Table 4-1. Switchpack S4 Definitions (Model 7974)Switch # . . . Allows you to . . .Default in Bold1 Enable or disable Switchpacks S3 and S4.OFF = Switchpacks DisabledON = Switchpacks Enabled2 Not used3 Select the unit’s primary timing source. Valid only for a unit configured asthe LTU.OFF = Internal ClockON = DSX-1 Clock4 Control the unit’s T1 line coding.OFF = B8ZSON = AMI5 Control the unit’s framing formatOFF = ESFON = D46, 7, 8 Control the unit’s line equalization. Refer to Table 4-2, Line Equalization,Switches 6–8 on Switchpack S4 (Model 7974), to set Line Equalization.The three switches form a binary value used as an index to the table ofequalization values. Off denotes 0 (zero) and On denotes 1 (one).000 (all OFF) = 0–133 feetTable 4-2. Line Equalization, Switches 6 –8 on Switchpack S4 (Model 7974)Switch PositionLine EqualizationDefault in Bold8 7 6OFF OFF OFF 0–133 feetOFF OFF ON 133–266 feetOFF ON OFF 266–399 feetOFF ON ON 399–533 feetON OFF OFF 533–655 feetON OFF ON 0–133 feetON ON OFF 0–133 feetON ON ON 0–133 feet
