Telenetics 56 User Manual
Page 116
AT&K Flow Control
The &K command enables you to select the type of flow control used between your modem and
the local computer when asynchronous mode is selected.You may want to do this to prevent
possible data loss resulting from buffer overflow.
the local computer when asynchronous mode is selected.You may want to do this to prevent
possible data loss resulting from buffer overflow.
Using flow control guarantees that data buffers in your modem and computer won’t
overflow.Your modem and your terminal or computer must be using the same type of flow
control.
overflow.Your modem and your terminal or computer must be using the same type of flow
control.
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Flow control is only available when your modem is configured for constant speed
mode or reliable or auto-reliable modes and is operating in on-line state.
mode or reliable or auto-reliable modes and is operating in on-line state.
Flow control will be ignored when your modem is configured for variable speed mode (AT\N1)
or is in local command state.
or is in local command state.
WARNING
XON/XOFF flow control must not be selected when you are using XModem, YModem
and SEAlink file transfers. XON/XOFF flow interferes with the operation of these file
transfer protocols and will cause unreliable operation.
and SEAlink file transfers. XON/XOFF flow interferes with the operation of these file
transfer protocols and will cause unreliable operation.
Options
AT&K0
Flow control disabled
AT&K3
■
RTS/CTS (hardware) flow control
The modem and computer use the CTS (Clear to Send) and RTS (Request to
Send) signals on the RS-232 serial connection to control data flow.
Send) signals on the RS-232 serial connection to control data flow.
AT&K4
XON/XOFF (software) flow control
The modem and computer use the XON and XOFF characters (DC1 and
DC3) to control the flow of data.
DC3) to control the flow of data.
AT&K5
Transparent XON/XOFF flow control
The modem and computer encode and decode XON and XOFF characters
which are part of the data stream.
which are part of the data stream.
Transparent XON/XOFF provides reliable operation when using file transfer
protocols.
protocols.
AT&K9
Failsafe flow control
When the modem’s data buffer approaches maximum capacity, the modem
will lower the CTS signal. If the computer subsequently sends more than 60
(S82) characters to the modem, the modem will send an XOFF character to
the computer.
will lower the CTS signal. If the computer subsequently sends more than 60
(S82) characters to the modem, the modem will send an XOFF character to
the computer.
When the modem is ready to accept more data from the computer it will
assert CTS and, if an XOFF was sent by the modem, will send an XON
character to the computer.
assert CTS and, if an XOFF was sent by the modem, will send an XON
character to the computer.
Failsafe flow control only affects data being transmitted from the computer
to the modem. Flow control is not supported for data being transmitted by
to the modem. Flow control is not supported for data being transmitted by