Cisco Systems DC-145 manual DC-150, Answer timeout

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Configuring and Managing External Modems

Supporting Dial-In Modems

Figure 24 EXEC Creation on a Line Configured for Modem Dial-In

Idle state

DTR low, watching

CTS

Ring transition

Raise DTR

Lower DTR

Answer timeout

Hang up

DTR low

Lower DTR

close connection

CTS lowered

or exit

DTR high

Ready and active

DTR high,

Ringing

watching

CTS

 

CTS raised

Create EXEC

S1001a

Note The modem callin and modem cts-requiredline configuration commands are useful for SLIP operation. These commands ensure that when the line is hung up or the CTS signal drops, the line reverts from Serial Line Internet Protocol (SLIP) mode to normal interactive mode. These commands do not work if you put the line in network mode permanently.

Although you can use the modem callin line configuration command with newer modems, the modem dialin line configuration command described in this section is more appropriate. The modem dialin command frees up CTS input for hardware flow control. Modern modems do not require the assertion of DTR to answer a phone line (that is, to take the line off-hook).

Cisco IOS Dial Technologies Configuration Guide

DC-150

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Contents External Modems on Low-End Access Servers DC-145Automatically Configuring an External Modem DC-146Using the Modem Autoconfigure Type Modemcap Feature Using the Modem Autoconfigure Discovery FeatureDC-147 Manually Configuring an External Modem DC-148Command Purpose Supporting Dial-In ModemsDC-149 Answer timeout DC-150Testing the Modem Connection DC-151Managing Telnet Sessions DC-152Suspending Telnet Sessions DC-153Modem Troubleshooting Tips Problem Likely CauseDC-154 Checking Other Modem Settings DC-155DC-156