US Robotics COURIER HST User'smanual page 27

COURIER HST
Non-MNP
Compatible,
2400, 1200 or
300 bps
FLOW
CONTROL
MAXIMUM
THROUGHPUT
HIGH-SPEED
CHANNEL
TURNAROUND
LINK
NEGOTIATION
3-2
See the flow control guidelines that follow.
Terminal/software: 2400. 1200 or 300 bps
Type:
AT &M0 D phone number <er>
NOTE: &M0 suppresses the MNP signals that may be mis-
interpreted by the remote system and prevent a successful
connection.
Hardware and/or software flow control can be used for
transmitted and received data. We recommend hardware
Transmit data flow control (&HI) since this setting doesn't
affect the data stream. This is especially important if you're
transmitting binary data.
Use flow control in any of the following situations.
• You're using error control (9600/2400/1200 bps). Flow
control prevents buffer overflow in the event that line
disturbances cause frequent retransmissions.
• The rate at the local terminal interface is higher than
the link rate.
• The volume of data transfer is high.
Flow control commands are covered in Chapter 4.
Use these settings for both Originate and Answer Modes.
Terminal/software:
Modem:
19.2k bps
Fixed terminal interface rate (&BI)
Variable link rate
(&N0)
Transmit Data flow control ( &H 1
preferred, &H2 or &H3)
As described in Chapter I, HST modems use asymmetric
modulation. The modems allocate the high-speed channel on
demand so that the modem with the greatest amount of data
in its buffer transmits at 9600 bps. Turnaround of the chan-
nel is automatic and requires no user intervention.
When a Courier HST calls an HST-compatible modem and
both are operating at 9600 bps, the modems negotiate the
link connection ("shake hands") at 2400 bps and automatic-
ally resume operation at 9600 bps. The lower handshaking
rate maintains compatibility with the existing telephone net-
work as well as existing hardware and software .