Sony IPELA PCS-XG100 Operating Instructions Manual page 194

• If you want to establish an ISDN connection after connecting to six or more
other points via IP, all other connections must be severed before connecting
to the ISDN terminal.
• The bit rate will be identical for terminals connected via ISDN and via IP.
For example, if a connection with a bit rate of 2 Mbps between each IP
terminal is made and a new connection with a bit rate of 2 B (128 Kbps) is
established with an ISDN terminal, the bit rate for both the IP and ISDN
terminals will be 128 Kbps.
194
Connection Examples of a Multipoint Connection