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Help Contents > Configuring the ISDN gateway > Configuring ISDN ports settings

Configuring ISDN Ports Settings

These settings affect the per-port ISDN configuration of the ISDN gateway. Use these settings to configure ISDN ports to

the requirements of your ISDN network. To access these settings, choose Home > Settings > ISDN ports, then select

the port of interest using the numbered links displayed.

Note that some ISDN configuration must be done on a unit-wide basis; see

Configuring General ISDN Settings.

Refer to the sections below for assistance configuring the ISDN ports settings. After making changes to any port, click

Apply changes. If you select a different port before clicking Apply changes, then any changes will be lost.

Port N settings

Field Field Description Usage Tips

Enabled

Selects whether this port may be used to

make and receive ISDN calls.

Directory Number

(DN)

Specifies the directory number of this ISDN

port.

This field is currently for information only

and is not used by the ISDN gateway when

making outgoing or receiving incoming calls.

Low channel

Specifies the lowest numbered B-channel

available.

An ISDN PRI comprises a number of B-

channels. A complete PRI has 30 available B-

channels when using E1, and 23 when using

T1 or J1. Your ISDN network provider may

offer a complete or fractional PRI (where a

reduced number of B-channels are

available). In either case, the low channel

number is generally 1.

Refer to your ISDN network provider if you

are unsure of which value to use here.

High channel

Specifies the highest numbered B-channel

available.

An ISDN PRI comprises a number of B-

channels. A complete PRI has 30 available B-

channels when using E1, and 23 when using

T1 or J1. Your ISDN network provider may

offer a complete or fractional PRI (where a

reduced number of B-channels are available).

Refer to your ISDN network provider if you

are unsure of which value to use here.

Channel search

order

Select whether free B-channels should be

selected starting with the low-numbered

channel and working towards the high-

numbered channel, or the other way around.

When making outgoing ISDN calls, the ISDN

gateway requests that the ISDN network

makes the call using a particular set of B-

channels; when receiving incoming ISDN

calls, the ISDN network informs the ISDN

gateway which B-channels are in use.

To minimize the risk of a new incoming call

using the same B-channels as a new

outgoing call starting at the same time, you

should generally set the ISDN gateway to

search free channels in the reverse order to

the ISDN network.

Refer to your ISDN network provider if you

are unsure of which value to use here.