Total Control MP/16, Operator'S Manual

Page: 52 / 182

3-16 Using Total Control MIBs
If the NMC is trying to transmit a packet out the Console port and
it doesn't detect the presence of CD, it attempts to set up a modem
on that port by issuing the AT command that the user has
configured via nmcCfgAtString.
Note that the default value of nmcCfgAtString is:
AT&FE0Q0&H1&R2&B1V1
This enables command mode local echo, verbal result codes, and
hardware flow control. These settings should be maintained for
proper functionality with the modem, but if other additional
settings are desired, they can be added to this string.
Next, the NMC proceeds to issue an AT dial command using the
phone number configured in nmcCfgWanDialOutPhoneNum. If
the process of dialing results in a successful connection (i.e., CD
becomes active), the packet is transmitted. If at least one packet is
received and/or transmitted every 60 seconds while an NMC-
initiated dial connection is up, the modems remain on-line, but if 60
seconds goes by without any SLIP traffic on the Console port, the
NMC drops DTR and hangs up the call.
NOTE:
On a dial-in call to the NMC, this idle time restriction
does not exist.
In the event that the NMC is not successful in making a dial-up
connection while attempting to transmit a packet from the Console
port, the NMC waits the number of seconds specified by
nmcCfgWanRetryPause (default=20 seconds) and retries the dialed
number. The NMC retries up to the number of times specified by
nmcCfgNumWanRetries before it gives up. If the number of retries
is exceeded, the NMC discards the packet it was trying to transmit.
If nmcCfgNumWanRetries is 0, the NMC tries to send that packet
forever and will not discard it.
Each unsuccessful dial attempt is counted by the NMC as a
connection attempt failure. If the number of connection attempt
failures exceeds the value configured in
nmcCfgNumFailBefSuspend (default=3), the NMC suspends dial
out attempts for the time specified by the value configured in
nmcCfgWanRetrySuspendTime (default=5 min). The purpose for
suspending such dial out attempts is to allow remote management
stations to dial in to the Console port. For example, if the remote
line is always busy and the NMC continuously tries to dial out,
remote management stations may be unable to dial in. Upon the