CTS  -   Clear To Send [DCE --> DTE]
DCD  -   Data Carrier Detected (Tone from a modem) [DCE --> DTE]
DCE  -   Data Communications Equipment eg. modem
DSR  -   Data Set Ready [DCE --> DTE]
DSRS  -   Data Signal Rate Selector [DCE --> DTE] (Not commonly used)
DTE  -   Data Terminal Equipment eg. computer, printer
DTR  -   Data Terminal Ready [DTE --> DCE]
FG  -   Frame Ground (screen or chassis)
NC  -   No Connection
RCk   -   Receiver (external) Clock input
RI   -   Ring Indicator (ringing tone detected)
RTS  -   Ready To Send [DTE --> DCE]
RxD  -   Received Data [DCE --> DTE]
SG  -   Signal Ground
SCTS  -   Secondary Clear To Send [DCE --> DTE]
SDCD   -   Secondary Data Carrier Detected (Tone from a modem) [DCE  --> DTE]
SRTS  -   Secondary Ready To Send [DTE --> DCE]
SRxD  -   Secondary Received Data [DCE --> DTE]
STxD  -   Secondary Transmitted Data [DTE --> DTE]
TxD  -   Transmitted Data [DTE --> DTE]