Ericsson ZAT 19.2 Operation Manual page 217

7.8 Key negotiation diagram.
Both modems are configured using encryption and the key- as well
as the password table is configured. The connect message is set to
+Q3- mode.
Calling modem
Answering modem
User dials .
ATDT37011710p%e]
Modem finds 37011710 in the
password list where it is marked using
encryption.
Modem auto answer and asks for
password.
ENTER PASSWORD ...
The message is received by the
modem. The password belonging to
number 37011710 is automatic
transmitted.
USER1
The password is received and
searched for in the password table, by
the modem. The password is marked
for the encryption with a K as well as
for the indexes 1 and 2. The modem
generates a string, containing the
user key index. This string is
encrypted with the key number O and
transmitted to the remote modem.
String with key index
The string is decrypted with key
number 0. The key index which should
be used together with the start block is
deducted from the string for
encryption.
The modem simulates a call towards
DTE and sends conneci message.
CONNECT 2400/REL/2400/V.42 CONNECT 2400/REL/2400/V.42
bis/ DES bis/ DES
LZTR104006 R1.00 7-23
Zat 14.4/14.4-7 and 19.2/19.2-7