Telebit T3000 Reference Manual page 159

Call in Progress (continued)
The modem uses two registers to control the flow of data
between the DTE and the modem. The S58 register
controls data flow over the Received Data (RD) line to the
DTE. A similar register, S68, controls data flow over the
Transmitted Data (TD) line to the modem. The two most
common flow control methods supported by the modem
are XON/XOFF or RTS/CTS.
Check your equipment's manual to determine which type
of flow control method it supports, and set the S58 and S68
registers to match that flow control method.
The DTE may not be responding to the flow control signal
soon enough to avoid a buff er overflow condition.
Did either modem unexpectedly stop transmitting or receiving
data?
The calling modem, answering modem, or both modems
may have been inadvertently placed in command mode by
a break signal or escape sequence. Registers S61 and S63
determine how the modem responds to a break signal. The
escape sequence, during a data connection, provides you
with a way to enter command mode. An escape sequence
contains three consecutive escape characters defined by
the S2 register and bordered by the proper guard time
specified by the S 12 register. You may need to change the
setting of these registers to prevent the modem from
entering command mode at an inappropriate time.
Note:
If the modem is installed in an unattended answer
environment, these registers should usually be set to
prevent entering command mode under any
condition.
7-16 Troubleshooting