Specifications

The Courier 1-5
SYN Synchronous Status
On The Courier is in synchronous mode.
Blinking Dial security is active.
Off The Courier is not in synchronous mode/dial security not active.
ARQ/FAX Error Correction/Fax
On Error correction is active.
Flashing The Courier is retransmitting data to the remote modem.
Blinking The Courier is in fax mode.
Off Error correction not active/not retransmitting data/not in fax mode.
Features
33.6 Kbps Connectivity
The Courier contains software that enables 31.2 and 33.6 Kbps
connection rates, as well as improves throughput at lower
speeds. While line conditions may not always allow for
33.6 Kbps connections, the new software makes it more likely
that your Courier will achieve and maintain 28.8 Kbps
connections. It can add up to 4800 bps to the average V.34
connection rate.
Selective Reject
Selective Reject is an optional part of the ITU V.42 (LAPM)
specification. This feature improves performance on noisy lines
by reducing the amount of overhead incurred when the protocol
must resend data due to errors.
When selective reject is active, only the frame that contained the
error is resent, instead of the frame plus all of the following
unacknowledged frames. You can disable selective reject by
changing a setting in S-Register 51 (see Appendix A, Alphabetic
Command Summary, in the Courier Modems Command
Reference manual).
Attaining Speeds Above 28.8 Kbps
V.34 connections at 21.6, 24.0, and 26.4 Kbps are common. To
get connections of 28.8, 31.2, and 33.6 Kbps, line quality must be
pristine end-to-end. In addition, 31.2 and 33.6 Kbps connection
rates are possible only when the device to which you are