User's Manual

Date Code 20041005 Instruction Manual SEL-3021 Transceiver
Introduction & Specifications
Product Overview
1.3
Figure 1.2 Secure SCADA Communications Channel
Encrypted Communications
Over an Insecure Channel
Insecure
Channel
SEL-3021
Modem
Modem
Modem
SCADA
Master
SCADA
RTU
Unauthorized
Device or
Attacker
Unauthorized
Communication
Blocked by an SEL-3021
Unauthorized
Communication
Blocked by an SEL-3021
SEL-3021
Preliminary Copy