Paradyne 3821PLUS manual Modem ± VF Connection, Table C-5

Troubleshooting

	Table C-5
	(1 of 2)
	Modem ± VF Connection
Symptom	Action
Modem does not receive a	Check the VF line connection. Verify dial tone at the source.
dial tone
Modem does not go	Verify that the Auto-Answer Ring Count configuration option (S-register 0) is set to a value
off-hook and answer an	other than 0 (disable).
incoming call	Verify that the DTE is providing DTR to the modem.
	If the DTE does not provide DTR to the modem, verify that the modem's &D command
	(DTR Action configuration option) is set for Ignore (&D0).
	Verify all cabling.
Modem goes off-hook,	Perform a Local Analog Loopback test and verify that data entered at the DTE is echoed
answers, but does not	back to the DTE.
connect	Verify that the originating modem is compatible.
	Verify that originating modem recognizes your modem's answer tone.
Modem goes off-hook,	Verify that originating modem supports your modem's modulation schemes. The 3821Plus
answers, but does not	modem recognizes V.34, V.32terbo, V.32bis, V.32, V.22bis, V.22, V.21, Bell 212A, and
connect (continued)	Bell 103J. It does not support other vendors' proprietary modulation schemes.
	Use the S41 register to force your modem to operate at the same modulation scheme as
	the originating modem.
Originate Mode	Verify that the modem's DTE Dialer configuration option is set to the correct setting.
Modem does not go	If using AT Dialing, refer to the Table C-4, Modem ± DTE Connection.
off-hook and begin dialing	If using DTR Dialing, verify the telephone number stored in directory location 1, and verify
	that the DTE is raising DTR from Off to ON to initiate a dial.
	If using V.25bis Async, verify that the correct character format is set to 7 data bits with even
	parity and 1 stop bit, and the carriage return and line feed are used as command
	terminators.
	If using V.25bis bisync, verify that the correct character format uses two synchronous
	control characters and a start-of-text control character before the text block and an
	end-of-text control character after the text block.
	If using V.25bis HDLC, verify that the correct character format uses flag, address, and
	control characters before the text block and a frame sequence check and flag after the text
	block.
Modem dials but does not	If the modem is operating behind a PBX, determine if a 9 and comma are needed before
connect	the telephone number.
	Determine whether Tone or Pulse dialing is needed.
	Verify if one modem is configured for Error Control or Disconnect and the other modem is
	configured for no Error Control. Try calling in Buffer mode.
	If both modems use V.34, V.32bis, or V.32 modulation, set the modem's Train Time
	configuration option to Long.

3821-A2-GB20-40 January 1999 C-3