Filter
Top Products
Guidelines
Installation
2-4 DBS-EX23-530 Revised April 2000
• 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 2-2 through 2-4 show 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.