US Robotics COURIER HST User'smanual page 101

COURIER HST
Example
Explanation
E-2.2
Action
I. Power on.
2. 300-bps call comes in.
3. Data link is established.
Data transfer takes place.
4. Data session is over.
Call is ended; loss of
earner.
Modem
Response
RING
CONNECT
NO CARRIER
DTE/DCE
Rate
9600
9600
9600
300
300
5. 2400-bps call comes in. RING
300
CONNECT 2400 300
6. Data link is established. 2400
Data transfer takes place.
7. Data session is over.
Call is ended; loss of
carrier.
NO CARRIER 2400
8. 9600-bps call comes in. RING 2400
CONNECT 9600 2400
9. Data link is established. 9600
Data transfer takes place.
10. Data session is over.
Call is ended; loss of
carrier.
NO CARRIER
9600
I. The modem is powered on and is operating at 9600 bps.
If the software is then set to 19. 2k bps and an AT com-
mand sent, the DTE/DCE rate would be 19.2k bps.
2. A 300-bps modem calls. The Courier senses the incom-
ing signal and sends the messages RING and CON-
NECT to the computer. These messages are sent at 9600
(or 19.2k) bps, the current rate.
3. Since the Courier responds CONNECT, rather than
CONNECT 1200, 2400, or 9600, the computer switches
to 300 bps. The modem automatically shifts to 300 bps
to accept the data from the incoming call.