Specifications

Serial Communications (82050)
Modem Status
Figure 11-5 shows the format of the Modem Status register. All eight
bits of this register are used to indicate the status of the serial data
transfer.
Register:ModemStatus
Address:03FEh
Access:Read/Write
76543210
DCTS
Delta Clear To Send
0 CTS has not changed
1 CTS has changed
DDSR
Delta Data Set Ready
0 DSR has not changed
1 DSR has changed
TERI
Trailing Edge Ring Indicator
0 No trailing edge received
1 Trailing edge received
DDCD
Delta Data Carrier Detect
0 DCD has not changed
1 DCD has changed
CTS
Clear To Send
0 Space
1 Mark
DSR
Data Set Ready
0 Space
1 Mark
RI
Ring Indicator
0 Space
1 Mark
DCD
Data Carriage Detect
0 Space
1 Mark
Figure 11–5. Modem Status Register.
11-15