Hardware manual

5901 High Speed Dialup Modem Hardware Manual

October 19, 2007

Minimum, maximum, and default values for S-Parameters may be altered with ConfigurACE.

10.2.3 A - Answer

The modem will go off-hook and attempt to answer an incoming call if correct conditions are met.

Upon successful completion of answer handshake, the modem will go on-line in answer mode. This

command may be affected by the state of Line Current Sense, if enabled. (Most countries do not

require Line Current Sense.) Operation is also dependent upon +FCLASS command and country-

specific requirements.

If +FCLASS=0 is selected, the modem will enter the connect state after exchanging carrier with the

remote modem. If no carrier is detected within a period specified in register S7, the modem hangs

up. Any character entered during the connect sequence will abort the connection attempt.

If +FCLASS=1, 1.0, or 2 is selected, the modem will go off-hook in V.21 answer mode. It will

generate the V.21 2100 Hz answer tone for 3 ± 0.5 seconds and, following a delay of 70 ms, will

proceed as if the +FTH=3 command were issued. At any stage up to (but excluding) the +FTH=3

command state, any character will abort the communication. (See the description of the +FTH

command for details.)

10.2.4 Bn - CCITT or Bell

When the modem is configured to allow either option, the modem will select Bell or CCITT

modulation for a line speed connection of 300 or 1200 bps. Any other line speed will use a CCITT

modulation standard. The parameter value, if valid, is written to S27 bit 6.

B0 Selects CCITT operation at 300 or 1200 bps during Call Establishment and a subsequent

connection. (Default.)

B1 Selects BELL operation at 300 or 1200 bps during Call Establishment and a subsequent

connection.

Result Codes:

OK n = 0 or 1.

ERROR Otherwise.

10.2.5 Dn - Dial

This command directs the modem to go on-line, dial according to the string entered and attempt to

establish a connection. If no dial string is supplied, the modem will go on-line and attempt the

handshake in originate mode. In W-class models, the action of going off-hook is affected by the

status of the Line Current Sense input, if line current sensing is enabled, and by the blacklist and

delayed list.

Note: If the ATD command is issued before the S1 register has cleared, the modem will respond

with the NO CARRIER result code.

If +FCLASS=0 is selected, the modem will behave as a data modem and will attempt to connect to

another data modem. The modem will have up to the period of time specified by register S6 or S7 to

wait for carrier and complete the handshake. If this time expires before the modem can complete the

handshake, the modem will go on-hook with the NO CARRIER response. This command will be

aborted in progress upon receipt of any DTE character before completion of the handshake.