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V.25 bis Command Set Operation
108.1 Mode Operating Procedures
Originating a Call Automatically
To establish communication by automatically originating a call in the 108.1 mode:
1. Prior to the time of calling a telephone number must be stored in the modem's memory cell 0.
That can be done with either the 108.2 mode PRN command or the AT command &Zn=nnn.
2. To initiate an automatically dialed call in 108.1 mode, turn On terminal interface circuit 108.1.
3. When communication is established with the remote modem, you may transfer data.
Originating a Call Manually
To establish communication by manually originating a call:
1. Lift the telephone handset, listen for a dial tone, and call the remote site.
2. When calling an automatically answered site, turn On terminal interface circuit 108.1— when
you hear answer tone from the remote modem.
3. When calling a manually answered site, ask the attendant who answers the call to transfer the
remote modem to data mode. When you hear answer tone, turn On terminal interface circuit
108.1.
4. When communication is established, you may transfer data.
Automatic Call Answering
The modem can answer calls automatically in 108.1 mode if the function has not been disabled. The
automatic answer enable/disable command (in 108.2 mode) is:
PRS AA ; n <LF>
where n is the number of rings (from 1 to 255) that the modem will wait before it begins the
automatic answering process.
PRS AA ; 0 <LF> disables automatic answering. The default is 4.
The following sequence of events takes place when them modem senses an incoming call:
1. After the specified number of rings, the modem turns On circuit 125 (Call Indicator) to alert
the DTE that an incoming call is trying to make a connection.
2. If the DTE is prepared to accept the connection it responds by turning On circuit 108.1. While
Call Indicator is On, circuit 108.1 acts as the command to perform automatic answering.
3. The modem then goes off-hook, performs handshaking, and — when that is successfully
completed — begins data transfer with the remote modem.
Manual Call Answering
When automatic answering is disabled, use the following procedure to establish communication by
manually answering calls:
1. When the telephone rings, lift the handset.
2. When the remote site attendant asks you to place the modem in data mode, turn On terminal
interface 108.1.
060R122-000
Issue 15
ITU-T V.25 bis Command Procedures
SpectraComm Dual V.34 Modem
Installation and Operation
5-11
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