Multi-Tech Systems BA-Series User Manual

Page 99

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99

Appendix D - V.25bis Operation

Dial Phone Number Provided (CRN) Command

The CRN command permits the dialing of the phone number immediately following it (from the
command line). It is similar to the

D command of the AT command set, except that the number is first

checked against the Delayed Number and Forbidden Number list. If permitted, depending on the
country regulations in effect, the number will then be dialed. For example, if you enter

CRN7859875

and hit RETURN, your modem will check the two lists. If the number is on the Delayed Numbers list,
you can dial that number again after

t minutes have passed. If the number is on the Forbidden list, a

CFIFC message will be displayed.

You can use various commands from the AT command set within the CRN command line to facilitate
the dialing process, such as

P, T, or : for pulse dialing, tone dialing and wait for dial tone. V.25bis

supports

“smart” dialing.

To dial a phone number, enter

CRNdd...dd where dd...dd is the phone number, which can be up to

20 characters long using any character on the telephone pad (0 through 9, *, #, P, T, and :).

Some additional dialing characters may be available, based on country regulations.

Listing Delayed Phone Numbers (RLD) Command

When a phone number is dialed by a CRN command and a connection is not made, the number is
entered in the modem's V.25

bis Delayed Number list along with the number of retry attempts. Any

further dialing attempts will be delayed some amount of time (determined by the regulations of each
country). While the delay is in progress, the modem will give a DLC indication. The list contains eight
numbers. When filled, the next number failing

“bumps” off the oldest number on the list onto the

Forbidden Number list. Numbers on the Delayed Number list that succeed in a connect attempt are
removed. If a certain number of failed attempts occur (the number of failed attempts is specified by
each country), the number is entered into the V.25

bis Forbidden Phone Number List. Forbidden

phone numbers cannot be dialed at all. To list the phone numbers on the V.25

bis Delayed Phone

Number List, enter

RLD and hit RETURN.

Listing Forbidden Phone Number (RLF) Command

Those phone numbers that have failed to connect the required number of times as specified by
country regulations are removed from the Delayed Number list and entered onto the V.25

bis

Forbidden Number list. Numbers on the Forbidden Number list cannot be dialed at all for some
maximum amount of time, which is also specified by country regulations. In some countries, the time
might be one hour, and in others the number may never be dialed again. The forbidden list is eight
numbers long, with the newest number replacing the oldest if the memory is full. To list the numbers
in the Forbidden list enter

RLF and hit RETURN.

Disregard or Connect to Incoming Calls (DIC or CIC) Command

The Disregard or Connect to Incoming Calls commands are used for Auto-Answer operations.
Depending on the country regulations, your modem will wait some amount of time or number of rings
before answering the call. During that time, you can stop the modem from answering the call by
entering the

DIC (Disregard Incoming Calls) command. CIC (Connect to Incoming Calls) command

will cause your modem to answer the call (either reversing the effect of a DIC command or simply
have your modem answer the call immediately without waiting the regulation time before answering).

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