polish documentation

README.md

@@ -1,13 +1,14 @@
 # tetra-pei
 
 The tetra-pei library allows to communicate with a TETRA radio terminal through its peripheral equipment interface (PEI), with the main focus on simple radio control and the handling of SDS messages. This implementation is solely based on the relevant ETSI specifications:
+
 * ETSI TS 100 392-2 V2.9.2 (2020-06): Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air Interface (AI)
 * ETSI EN 300 392-5 V2.7.1 (2020-04): Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D) and Direct Mode Operation (DMO); Part 5: Peripheral Equipment Interface (PEI)
 
 ## Restrictions
 
 * store/forward control information is not handled
-* the only supported text encoding scheme is ISO8859-1
+* not all specified text encoding schemes are implemented
 
 ## License