Setting The Modem; Modulation/Link Rate Guidelines - US Robotics COURIER User Manual

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COURIER HIGH SPEED MODEMS
a synchronous adapter card. These cards are multifunction
boards that provide the following functions:
• A synchronous port from the DTE to the modem.
• One or more synchronous protocols. Be sure to find out
which protocol the Host mainframe requires before you
purchase an adapter.
• Additional software functions. For example, you need
to identify the type of computer or terminal you are
using to the mainframe software. You will most likely
also have to specify your application, that is, identify the
mainframe resources you want to use.
SETTING THE MODEM
Once the modem is in synchronous mode it no longer recognizes
commands. Before attempting to connect in a synchronous net-
work, use the following instructions to configure the modem
while it is still in asynchronous mode.
NOTE: Be sure that DIP switch 1 is OFF (factory setting). The
Data Terminal Ready (DTR) override must be OFF so that the
Courier detects when the DTE raises and lowers the DTR signal.
To set the modem, follow the instructions for issuing commands
to the modem that are in Chapter 2, Testing the Installation.
Commands begin with a required AT prefix and end with a
required Carriage Return, which we denote with the symbol
<Enter>. For example, the following command sets the modem
to synchronous mode:
AT &M1 <Enter>
Modulation/Link Rate (Bn, &Nn)
Use the following guidelines for your Courier type.
V.32 bis modems: If the modem is connecting with another
USRobotics V .32 bis modem, set both modems to BO and to a
variable link rate, &NO. The modems will connect at the highest
possible rate.
If the Courier V.32 bis is to connect with a V.32 modem, set the
Courier to BO and try a variable link rate first, &NO. If that
Synchronous Operations 7-3