User's Manual

TS4000 Radio Modem User’s Manual Appendix A - Serial Ports 51
Level (volts DC)
Type Low High
Output (Driver) 0.0 to +0.4
(sinking up to 4 mA)
+3.0 to +5.0
(sourcing up to 4 mA)
Input (Receiver) -25 to +0.8 +2.4 to +25
(3k to 7k ohm load)
The signal polarity is the same for both RS-232 and TTL operation.
Level State
Voltage Low Mark
Control signal inactive
Stop bit state (end of async character)
Logic one data bit state (within async character)
Voltage High Space
Control signal active
Start bit state (beginning of async character)
Logic zero data bit state (within async character)
TTL Signal Levels
Signal Polarity