Philips manual Guidelines Installation, DBS-EX23-530 Revised April

Guidelines Installation

•Fractional ISDN can be used when fewer than 23 ISDN trunks are needed. Fractional ISDN allows you to use only a portion of the 23 channels provided on the ISDN card.

•Fractional ISDN per port assignments require the VB-43511A version of the loop start trunk card. The older VB-43511 version may be used with fractional ISDN but requires that the trunks be assigned in blocks of 8.

•Though each ISDN Interface provides 23 trunk channels, ISDN trunks do not increase the overall trunk capacity of the DBS. Each ISDN channel subtracts from the total number of analog trunks that can be installed. The number of analog trunks that can be used are decremented in quantities of 1 for each ISDN channel user.

Tables 2-2through 2-4show the possible combinations of analog and digital trunks assignments based on system size.

The trunk numbering shown in these tables is determined by backplane trunk port assignments. Therefore, the numbering cannot be changed.

Note: Analog trunks are numbered beginning with “1.” ISDN trunk channels are numbered beginning with the highest trunk channel used.

2-4 DBS-EX23-530 Revised April 2000