Link Rate Select (&Nn) - US Robotics COURIER User Manual

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COURIER HIGH SPEED MODEMS
To implement this feature, set the modem to return ARQ
CONNECT result codes, &Al or &A2, and to Transmit
Data flow control, preferably &Hl. Set your software to
the desired rate, and send the modem an AT &82 [other
settings] &W command string.
The modem stores the rate of the command in NVRAM
along with the settings. Each time it makes an ARQ
connection, the modem checks NVRAM for the specified
DTE rate.
When sending subsequent configurations to NVRAM, be
sure your software is set to your selected DTE rate, so that
the correct rate is maintained.
Link Rate Select (&Nn)
Use this command to select variable or fixed rates at the link
interface. Variable rates allow the modem to connect with a
variety of remote modems.
&NO Variable rates. Default. The Courier negotiates with the
remote modem for the highest possible link rate, depend-
ing on the capabilities of the remote modem. This is the
recommended setting.
&N1-9Fixed rate. The modem only connects if the remote
modern is operating at the same rate.
If
not, the modem
hangs up.
The link rate must always be lower than, or equal to, the
DTE rate, never higher. If the link rate is lower than the
DTE rate, enable Transmit Data flow control, preferably
hardware control (&Hl), so that the modem's buffer
doesn't overflow.
If you wish, you can filter out calls at other than a specific
speed, for security or other reasons, by fixing the link rate.
Interface Controls 4-15