pcsc-relay: updated docs

pcsc-relay/README.md

@@ -2,7 +2,7 @@
 
 Welcome to PC/SC Relay. The purpose of PC/SC Relay is to relay a smart
 card using an contact-less interface. Currently the following contact-less
-emulators are supported:
+**emulators** are supported:
 
 - Hardware supported by [libnfc](http://www.libnfc.org/)
 - OpenPICC
@@ -11,7 +11,7 @@ emulators are supported:
 
 Command APDUs are received with the contact-less interface and relayed. The
 Response APDUs are then sent back via RFID. The contact-less data will be
-relayed to one of the following:
+relayed to one of the following **connectors**:
 
 - to a *real* smart card inserted into one of the systems' smart card readers.
   The smart card reader must be accessible with PC/SC. The smart card may be
@@ -21,3 +21,27 @@ relayed to one of the following:
   directly connects to `pcsc-relay`. The virtual smart card's native interface
   is used and (despite its name) PC/SC Relay does not need to access PC/SC in
   this case.
+
+<!---
+http://www.plantuml.com/plantuml/txt/SoWkIImgAStDuNBDBSr9BCalKj2rKr0gI2vErYrApKciL5AmKd3EpyrDp4jHS0nm2UL2bWEg1KhcvQKc0pLoGLcOHc3eWTjbfH2KMboGdrUS2Z7S8JKl1UWO0000
+
+@startuml
+skinparam responseMessageBelowArrow true
+Emulator -> "pcsc-relay" : Command APDU
+"pcsc-relay" -> Connector
+Connector -> "pcsc-relay"
+"pcsc-relay" -> Emulator : Response APDU
+@enduml
+-->
+     ┌────────┐          ┌──────────┐          ┌─────────┐
+     │Emulator│          │pcsc-relay│          │Connector│
+     └───┬────┘          └────┬─────┘          └────┬────┘
+         │    Command APDU    │                     │     
+         │ ───────────────────>                     │     
+         │                    │ ───────────────────>│     
+         │                    │ <───────────────────│     
+         │    Response APDU   │                     │     
+         │ <───────────────────                     │     
+     ┌───┴────┐          ┌────┴─────┐          ┌────┴────┐
+     │Emulator│          │pcsc-relay│          │Connector│
+     └────────┘          └──────────┘          └─────────┘