5.2 OPERATING THE SYNCHRONOUS DATA PORT
The synchronous data port is a variable rate Universal DCE port.
Since both voice ports and framing/signaling information require 64Kbs,
the remaining bandwidth is used for the data port.
The physical interface of the Data Port is a female, High Density
DB-26. The electrical interface is user configured as a V.35, EIA-232,
or EIA-422. The configuration is accomplished via dip switches on the
module. At present, the design uses a "gapped" clock approach. The
clock sent from the module to the DTE terminal is halted during voice
and framing transmission. With the gapped clock approach, the clock
period of the host module is the period of the DCE clock. The effective
data rate at the DCE port is the host data rate minus 64Kbs.
5.3 FXS to FXO APPLICATIONS:
Figure 5 depicts a typical FXO to FXS application. A Model 1092
with an FXS VDQM acts as an extension of two PSTN phone lines,
which is connected to the 1092 with an FXO VDQM. In this example,
calls dialed into 555-1111 will automatically be sent to the fax machine
connected to Port 1 of Unit 2. When the handset of the phone
connected to Port 2 of Unit 2 is lifted, the phone line of Port 2 Unit 1 will
go off hook, passing dial tone and allowing for DTMF dialing. A router
connected to the Data port of Unit 2 can control the modem connected
to the data port of Unit 1.
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1092 e/w FXO port
1092 e/w FXS port
Public Switch
Port 1
Port 2
DCE
DCE
Port 1
Port 2
2 Wire
FAX
555-1111
555-2222
UNIT 1
UNIT 2
Modem
555-3333
Router
Figure 5. Typical FXS to FXO Application
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5.4 FXS to FXS APPLICATIONS:
Figure 6 depicts a typical FXS to FXS application. The fax
machine connected to Port 1 on Unit 1 will communicate with the FAX
machine connected to Port 1, Unit 2. Phone numbers are not required
for the FXS modules but may be required for the fax machine to
operate properly. If a fax is to be sent from Unit 1 to Unit 2, a 'dummy'
digit can be entered into FAX 1 (NOTE: the fax machines must be set
to ignore dial tone). When the FAX 1 is given the send command, Port
1 unit 1 will go off-hook. The IM1/J will then send signaling bits to Unit
2, instructing Unit 2 Port 1 to ring. Fax 2 will answer the ring and
normal Fax traffic will commence.
To initiate a voice call, either phone is picked up, the phone at the
far end will ring. Once the phone at the far end is answered, both units
will go into voice mode and a conversation can be held.
1092 e/w FXO port
1092 e/w FXS port
Port 1
Port 2
DCE
DCE
Port 1
Port 2
2 Wire
FAX
Mainframe
FAX
Unit 1
Unit 2
Bridge
Figure 6. Typical FXS to FXO Application
