401. Establishes the connection of access to the PBX by using an idle port (L2 or L4).2. If SYS_4_5_[2] is specified, waits one second and then starts Step 3. If not, starts the dial tonedetection:- When the dial tone is detected, start Step 3.- If 3-second silence is detected, abandons the following actions and plays the main greeting asreceiving an incoming call.3. Dials the C.O Trunk Group Access code specified in SYS_6_5.4. Waits two seconds and then dials the pager number.5. Waits three seconds.6. Waits for the paging system response till a tone or 6-second silence is detected.7. Waits 1.2 seconds and then dials the Personal Identification Number. If there is not a PIN, dialsthe System Callback Number specified in MB9999_VM_5.8. Hangs up. The VM_5 setting of a general mailbox may include two parts: the first part specifies a pagernumber; the second part may or may not specify a Personal Identification Number. A pager number must not include any *, #, A, B or C because either of them will cause thesystem to start Step 5. A Personal Identification Number must begin with a *, #, A, B or C. A digit of C (entered bypressing * 4) represents an XX-second pause, the length of which is specified in SYS_2_0. Usually, the System Callback Number is a telephone number to inform pager owners totelephone the EVM system. It will be not sent out if a Personal Identification Number is sentfollowing the pager number.External Phone NotificationTo deliver the Notification greeting (paragraph 22) to a personal external phone, EVM will take thefollowing actions:1. Establishes the connection of access to the PBX by using an idle port (L2 or L4).2. If SYS_4_5_[2] is specified, waits one second and then starts Step 3. If not, starts the dial tonedetection:- If a tone is detected, start Step 3.- If 3-second silence is detected, abandons the following actions and plays the main greeting asreceiving an incoming call.3. Dials the C.O Trunk Group Access code specified in SYS_6_5.4. Waits two seconds and then dials the phone number.5. Waits for the Tone Detection delay specified in SYS_7_3.6. Handles the call, according to the result of the tone detection:- If the busy tone is detected, hangs up.- If the ringback tone is detected, monitors the successive ringback tone cycles. Plays theNotification greeting (paragraph 22) when the mailbox owner answers. Hangs up when theringback tone continues for 30 seconds. SYS_3_3 determines the maximum number of External Phone Notification attempts. The