US Robotics COURIER HST User'smanual page 46

BASIC
REQUIREMENTS
Transmission
Rate
Error Control
COURIER HST
CHAPTER 6
DIALING AND ANSWERING
To successfully establish a communications link, the called
or calling modem must be compatible with the following
standards at the specified bit rates.
Bits per
Second
9600
2400
1200
300
Standard
USR-HST or compatible
CCITT V.22bis
Bell 212A
Bell 103
To successfully exchange data, both modems must use
the same I 0-bit data format. The formats allowed are as
follows:
Start Data
Bits Bits
7
7
8
Parity
Even, Odd,
Mark, Space
None, Even. Odd.
Mark, Space
None
Stop
Bits
2
1,2
In general, you should know the transmission rate of the
other modem before calling. However, if the link rate is set
to the default, &N0, and the Courier HST tries to connect
with a modem operating at a lower rate, the Courier falls
back to the rate of the remote modem. This applies to both
Originate and Answer Modes.
>
See the discussion under
"Data Rate Commands," in Chapter 4.
Always set the Courier HST for error control. &M4 (the
default) or &MS, for 9600 bps connections.
It helps to know if the remote modem is MNP-compatible at
2400/1200 bps. Some public network services, for example,
are not. When the Courier HST is set to &M4 it includes
an error-control link request in its handshake signals. If the
remote modem isn't under error control, the Courier oper-
ates in Normal Mode (no error control). However, if the
remote modem doesn't support the MNP protocol at 2400
6-1