User guide

Features

Up to 4 calls can be made simultaneously via an RPF, and up to 8

calls can be made simultaneously if an RFP is connected via 2 U

connections. The DECT network can also be operated using VoIP

(see DECT over IP

starting on page 140).

Voice over IP (VoIP)

Forum 523/524 supports the connection of VoIP terminals, ena-

bling the company’s existing internal network infrastructure (LAN

with 100 MBit/s) to be used for telephony as well. Corded system

terminals of the Forum IPhone 525 and Forum IPhone 535 as well

as the VoIP system telephones Forum IPhone 520 and

Forum IPhone 530 types are available for this purpose. These

devices have the same functionality and support the same fea-

tures as the non IP-enabled system terminals.

The eight gateway channels of an installable Media Gateway card

are automatically switched on for telephone calls between IP ter-

minals and ordinary terminals, for data compression, for the gen-

eration of DTMF and dial tones and for echo suppression. It is also

possible to use a limited range of VoIP functions without an addi-

tional Media Gateway card. The system software provides up to 32

uncompressed VoIP gateway channels without echo compensa-

tion.

For users wanting to use PC-supported telephony, IP system ter-

minals are available as separate licensable software versions

(“Softphone”). You will find further information on this in the

chapter on Voice over IP (VoIP) starting on page 101.

VoIP with media gateway card

Additional VoIP features can be used by installing a media gate-

way card with the communications system Forum 523/524.

z SIP (internal): You can operate SIP system phones

Forum IPhone 512 / Forum IPhone 545 and standard SIP

telephones.

z SIP (external): You can use external SIP connections as “SIP

trunk lines”. Setting up and using external SIP connections is

completely transparent for telephone users, providing them

with easy access to low-cost Internet telephony and a fallback

to normal ISDN connections in case of error or busy lines. A

Media Gateway card is required for SIP telephony.