DCP Configuration
4-353920-A2-GN31-30 November 1996
Table 4-7
(3 of 8)DTE Interface Configuration Options — Singleport Mode A
DTR Action: Ignore
Nxt Ignore Stndrd_RS232 CntrlsOnHook CntrlsTxMute
Data Terminal Ready Action. DTR is a signal from the DTE to the modem indicating that the DTE is connected and
ready for operation.
Ignore – Modem assumes DTR is always ON. This is used when the DTE does not provide DTR.
Standard RS232 – Allows the DTE to control DTR to the modem as specified in EIA-232-D and CCITT V.24
specifications. If this signal is not present, the modem will not answer or dial.
Controls On-Hook – Required for applications in which the host processor must reset itself for the next session before
the current session is terminated. When selected, the modem does not disconnect from the VF line during an active call
until DTR is lowered by the attached DTE. This setting is ignored if the modem is commanded to disconnect from its
own front panel or by the COMSPHERE 6700 Series Network Management System.
Controls Transmitter Mute – Mutes the transmitter whenever DTR drops on the DTE interface. This selection is valid
only in the V32bis modulation and can be used on the answer side modem to force the originate modem to initiate a dial
backup.
NOTE: If V.25bis mode is used, then this configuration option must be set to Stndrd_RS232. The DTE must provide
DTR to dial or answer a call.
NOTE: When operating over the dial network, this selection forces DTR Action to behave as CT108/2 (Data Terminal
Ready). If DTE Dialer Type configuration option is set to DTR=Direct 1, then DTR Action behaves as CT108/1
(Connect Data Set to Line).
The AT command for Ignore is &D0.
The AT commands for Standard RS232 are &D1, &D2 or &D3.
The AT command for CntrlsOnHook is &D4.
The AT command for CntrlsTxMute is &D5.
DSR Control: Stndrd_RS232
Nxt Stndrd_RS232 Forced_On WinkWhenDisc Follows_DTR On_Early Delay_ToData
Data Set Ready Control. DSR is a signal from the modem to the DTE indicating the modem is connected and ready for
operation.
Standard RS232 – Allows the modem to control DSR to the DTE. The modem raises DSR when it begins the
handshake process. DSR lowers upon disconnect. The modem is not ready to receive data until DSR, CTS, and LSD
are active. An ON state indicates to the DTE that the modem is ready to receive data. An OFF state indicates that the
modem is not ready to receive data, and the DTE will not send data to the modem. During a Local Analog Loop and a
Remote Digital Loop, DSR is ON.
Forced On – Forces DSR output ON constantly. This is usually used for leased-line applications and when the DTE
requires DSR to always be ON.
Wink When Disconnect – DSR is normally forced ON, but is turned OFF for 1 to 2 seconds upon a disconnect.
Follows DTR – When the modem receives DTR from the DTE, it sends DSR to the DTE.
On Early – DSR is low when the modem is in the idle state. DSR goes high immediately upon a command to enter Data
mode. This setting is required for some modem pooling applications.
Delay to Data – Operation is similar to the Standard RS232 except that DSR does not turn ON until the modem enters
Data mode. Normally, the modem raises DSR when it begins the handshaking process. Use this setting when the DTE
cannot operate with a long DSR-to-CTS delay (common for V.32bis modulation) or when dial access security is enabled
and requires a DTE-side password entry. Often, the DTE cannot accept the long delay between DSR and CTS turning
ON due to the remote user entering the DTE-side password.