Nortel T1/SMDI Configuration Manual page 179

February 2008
CallPilot SMDI link RS-232 multi-character serial data
transmission characteristics
RS-232 can be used to convey indefinitely long strings of ASCII characters
asynchronously, when idle state gaps are used as character delimiters, as
shown in the following illustration:
Multi-character asynchronous serial transmission
Logic 0
Logic 1
Idle state
• Least significant bit is first
• Idle state and start state are opposite
• Stop bit is the same as idle state
CallPilot SMDI link RS-232 connector pinouts
The EIA/TIA-232-F RS-232 standard provides details of RS-232
compatible connectors for interconnections; however, the DB-25 and DB-9
connector pinouts used most frequently are provided below for convenience.
9-pin AT style connector
Pin number
1
2
3
4
T1/SMDI and CallPilot Server Configuration
Start of the first character
0 1 1 0 1 0 1 0 1 1
RS-232 signal names
Data carrier detect
Received data
Transmitted data
Data terminal ready
Start of the second character
P Stop
0 0 1 1 0 1 1 0 1 1
Idle state
CallPilot T1/SMDI interfaces
P Stop
Idle state
g250067
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