Specifications

Configuring the Modem
SW1-8 − Anti-streaming
SW1-8 ON = Anti-streaming active
OFF = Anti-stream inactive
Typically, anti-streaming is used in multi-point applications to prevent a malfunctioning slave modem from
occupying the line indefinitely. When anti-streaming is active, the modem can transmit data for a maximum of 27
seconds before the transmitter turns off automatically. The modem then looks for an ON-to-OFF Request To Send
(RTS) transition before proceeding with normal operation. Anti-streaming can be selected in either high-speed or
low-speed mode.
SW2 DIP Switch Settings
SW2 is an 8-position DIP switch. Table 2-3 shows the modem switch settings for DIP switch SW2. A description of
the SW2 switch settings follows the table.
Table 2-3. Modem Switch Settings for DIP Switch SW2
Switch Settings Switches
ON OFF (Default)
SW2-1: FSK Mode (page 11) V.23 Bell 202
SW2-2: Receiver Squelch (page 12)
(valid for FSK mode, 2-wire half-duplex
operation only)
Turnaround Squelch (Bell 202): 8ms
Turnaround Squelch (V.23): 150ms
Turnaround Squelch (Bell 202): 0ms
Turnaround Squelch (V.23): 0ms
SW2-3: FSK Soft Carrier (page 12) Disabled Enabled
SW2-4 and SW2-5: FSK RTS-CTS Delay
(page 12)
(see Table 2-4)
SW2-6: FSK CD Delay (page 13) 23ms 6ms
SW2-7: Remote Loopback (page 13) Enabled Disabled
SW2-8: Reserved (Test Only) (page 13) Test Normal
SW2-1  FSK Mode
SW2-1 ON = ITU-T V.23 mode
OFF = Bell 202 mode
The modem has two FSK modes:
 Bell 202, which supports data rates from 0 to 1800 bps
 ITU-T V.23, which supports data rates from 0 to 1200 bps
SW2-1 configures the modem for either of these FSK modes. Setting SW2-1 to ON selects ITU-T V.23 mode. In
this mode, the modem complies with ITU-T (CCITT) recommendation V.23 with the following parameters:
 Mode 2 modulation only
 No backward channel
Page 11