Section 300-Installation Chapter 4. Trunks and LinesDBS-2.3/9.2-300 DBS Manual - Revised April 2000 4-13Table 4-8. T1 slot usage for two-cabinet systems• Fractional T1 can be used when fewer than 24 T1 trunks are needed.Fractional T1 allows you to use only a portion of the 24 channels providedon the T1 card.• Though each T1 Interface provides 24 trunk channels, T1 trunks do notincrease the overall trunk capacity of the DBS. Each T1 channel subtractsfrom the total number of analog trunks that can be installed.• With CPC-B earlier than 5.00, the number of analog trunks that can beused with Fractional T1 are always decremented in quantities of 8.For example, if you are installing a T1 in a DBS 96 and you only want touse 12 T1 channels, the logical number of analog trunks that would beavailable is 20 (32 - 12 = 20).The number of analog trunks must be decremented in quantities of 8, theactual number of analog trunks that can be used is 16:(32 total trunks - 16 (two 8-trunk increments) = 16.)Tables 4-9 through 4-11 show the possible combinations of analog anddigital trunks assignments based on system size.The trunk numbering shown in these tables is determined by backplanetrunk port assignments. Therefore, the numbering cannot be changed.• With CPC-B 5.00 and higher and the VB-43511A Loop Start Trunk Card,the number of analog trunks that can be used with Fractional T1 aredecremented in quantities of 1.Note: Analog trunks are numbered beginning with “1.” T1 trunk channelsare numbered beginning with the highest trunk channel used.System Size EC/TRK Slot Usage for T1Master SlaveDBS 40 + DBS 40 No YesDBS 72 + DBS 40 No NoDBS 72 + DBS 72 No YesDBS 96 + DBS 40 Yes YesDBS 96 + DBS 72 Yes YesDBS 96 + DBS 96 Yes Yes
