Data Buffer For Serial Data Transmission; Bit Direct Mode; Hardware Data Flow Control With Rts/Cts - Siemens Insys 56k Operating Manual

Function
5.2.2

Data Buffer for Serial Data Transmission

The modem has a fast send and receive cache (so-called buffer) to
adjust the modem to the PC operating speed. It is, however, possible
to deactivate this data buffering and switch to bit direct mode.
When working with buffers, handshake must be used, because
otherwise an overflow could occur which might lead to data
transmission errors.
5.2.3

Bit Direct Mode

Only for special, non-standard data formats
In bit direct mode, the modem has no influence on the
transmission format. The data is transmitted without buffering.
Data compression or error correction will not work in bit direct
mode. Only the abort sequence - default +++ - is utilized by the
modem.
5.2.4

Hardware Data Flow Control with RTS/CTS

Hardware Data Flow Control with the Modem (CTS).
Modem
When the input buffer of the modem exceeds a certain fill state,
the modem will set the CTS line to OFF. This will indicate to the
modem not to send any more data.
After the modem has operated the input buffer so far that the
XON buffer falls below a certain fill state, it switches the CTS line
on and reports to the PC that it is ready to receive data again.
8
RS232 Cable
CTS Line
PC or control
Pocket Modem 56K
AT\N1
AT&K3 AT&R1
Dezember 05