User's Manual

Appendix A Hayes Commands
Man_455U Rev 1.0 Page 53
Switch.
AT&K RS-232 Serial port Flow Control Configuration. Flow control options are: none,
CTS/RTS and XON/XOFF.
In Acknowledged mode, flow control passes across the modem link, as the local
buffers become full, then back to the remote host device as the remote modem’s
buffers become full.
No Flow control is provided on the RS-485 port.
&K0•
Flow Control Disabled. CTS Always high. Modem ignores RTS.
&K1 CTS/RTS Flow Control. CTS follows RTS high if there is space in the local
buffer. Otherwise CTS goes low. On Serial Transmit, CTS goes high, and waits
for RTS to go high before transmitting. Note: Currently not implemented
(Behaviour is as for &K3)
&K2 CTS/RTS Flow Control. CTS Reflects the state of the remote buffer, AND the
local buffer, AND the remote RTS input. The modem only transmits serial data
when RTS is high. RTS input is transferred to the remote modem. Note:
Currently not implemented (Behaviour is as for &K3)
&K3 CTS/RTS Flow Control. CTS Reflects the state of the local buffer. Modem only
transmits serial data when RTS is high.
&K4 XON – XOFF Flow Control. Modem uses XON (Hex value 0x17) and XOFF
(Hex value 0x19) to control flow of information between modem and host.
AT&L Leased Line Mode Control. Allows configuration for answer, originate, or
command mode.
&L0•
Normal Mode. At power-up, the modem enters command mode and waits for
commands.
&L1 Leased Line mode. For Acknowledged mode, ATD automatically dials the
number stored in Z0, ATA answers an incoming call. For Unacknowledged
modes, the modem automatically goes online, and sends messages to the modem
configured in Z0.
&L2 Leased Line Originate mode. The modem dials the number stored in &Z0
automatically. It continuously attempts to connect to that number. Use DTR with
the AT&D command to control the connection. This mode is only allowed when
operating in Acknowledged mode.
&L3 Leased Line Answer mode. The modem continuously attempts to answer any
incoming call. Use DTR with the AT&D command to control the connection.
This mode is only allowed when operating in Acknowledged mode.
AT&M Operating Mode. This allows selection between unacknowledged mode,
acknowledged mode and the different protocol specific modes.
&M0•
Unacknowledged Mode. All serial data is sent to the configured destination
address (In Z0 or specified in a dial command). No Acknowledgement is
required, and broadcast messages are allowed by using the wildcard address “0”.