User's Manual

Appendix A Hayes Commands
Man_455U Rev 1.0 Page 59
AT&C Data Carrier Detect (DCD) Control. DCD is always on in Unacknowledged mode.
&C0 DCD Always on.
&C1•
DCD High when connected (Acknowledged Mode). Low otherwise.
&C2 DCD Always on, Pulses low on Disconnect (Acknowledged Mode).
AT&D Data Terminal Ready (DTR) Behaviour. The host controls DTR. This command
controls how the modem reacts to the state of DTR.
&D0•
Modem ignores DTR, and acts as if it is asserted.
&D1 If the host lowers DTR, the modem returns to command mode, but does not
disconnect.
&D2 If the host lowers DTR, the modem disconnects and returns to command mode.
&D3 If the host lowers DTR, the modem disconnects and goes to low power mode.
Raising DTR will cause the modem to dial if the leased line settings are correct
(&L1).
AT&E CRC Error Checking
&E0•
Disable CRC Error Checking
&E1 Enable CRC Error Checking
AT&F Restore Factory Defaults. This function is also available from the external DIP
Switch. Changed to S-Register
AT&H Broadcast Repeater Hops Setting – Set the number of hops for a message to
activate the broadcast repeater function (AT&R).
&H0•
Don’t repeat messages to the “Wildcard” address, and don’t copy repeated
messages out the local serial port, regardless of the AT&R setting.
&H1 Perform the action specified by the AT&R setting when the wildcard address is
the first Store&Forward address, and the message has completed one hop.
&H2 Perform the action specified by the AT&R setting when the wildcard address is
the second Store&Forward address, and the message has completed two hops.
&H3
.. &H6
Repeat Messages when the wildcard address is the third (.. sixth) Store&Forward
address, and the message has completed three (..six) hops.
AT&K RS-232 Serial port Flow Control Configuration. Flow control options are: none,
CTS/RTS, XON/XOFF and RS-485 mode. 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 Reflects the state of the local buffer. Modem only
transmits serial data when RTS is high.
&K2 As for &K1
&K3 As for &K1
&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.