Specifications

 No provisions for disablement of echo suppressors
 DTR (circuit 108) is ignored
Setting SW2-1 OFF selects Bell 202 mode.
SW2-2  Receiver Squelch (FSK Mode 2-Wire Half-Duplex Only)
SW2-2 ON = 8ms for Bell 202, 150ms for ITU-T V.23
OFF = 0ms
SW2-2 configures the turnaround squelch delay and is valid when the following are active:
 FSK mode (SW3-1 ON)
 2-wire half-duplex operation (SW3-7 ON)
Setting this switch to OFF configures the modem to enable its receiver immediately after the Request To Send
(RTS) signal is turned off. When this switch is set to OFF and the modem is configured for 2-wire, half-duplex
mode (SW3-7 ON), the modem squelches the receiver after RTS is turned off to prevent far-end echoes from
causing data errors. The duration that the modem squelches the receiver is either:
 8 milliseconds if the modem is configured for Bell 202 mode (SW2-1 OFF)
 150 milliseconds if the modem is configured for ITU-T V.23 mode (SW2-1 ON)
SW2-3  FSK Soft Carrier (Bell 202 FSK Mode Only)
SW2-3 ON = None
OFF = 8ms
SW2-3 controls the soft carrier and is valid for Bell 202 FSK mode only (SW2-1 set to OFF). Setting this switch to
OFF configures the modem to transmit a 900 Hz soft carrier to the remote modem for 8 milliseconds after RTS is
turned off. Setting this switch to ON prevents the modem from transmitting a soft carrier after RTS is turned off.
SW2-4 and SW2-5  RTS-CTS Delay (Bell 202 Mode Only)
Switches SW2-4 and SW2-5 determine the duration of the RTS-CTS delay in Bell 202 mode. Table 2-4 shows how
to set these switches to select the appropriate setting.
Table 2-4. RTS-CTS Delay Settings in Bell 202 Mode
To Select a Delay of… Set SW2-4 to… And Set SW2-5 to…
8ms OFF OFF
33ms OFF ON
59ms ON OFF
219ms ON ON
Page 12