Specifications

Defining Operating Parameters
5-51
Switch Type
This parameter allows you to define the switch type and software protocol. This
parameter setting must correspond with your dial line connection. The available options
are:
• NI-1 - National ISDN-1 standard.
• NT100 - Northern Telecom DMS-100 at a functional Pvc0 protocol.
• AT&T - AT&T 5ESS with Custom, 5E6, or later software.
Dial Mode
This parameter allows you to select the dial mode. When EISDN is selected, you can
enable the Route Secondary Channel To Dial feature and the dial backup security feature
during dial backup operation. Select ESw56 when operating with another DAP with
SW56 IDBU or when the telephone company only provides 56 Kbps for customer data
on the ISDN service. Select ISDN when the service is set for DDS, DDS-SC, CC64,
LDM, or LADC.
Transmit Clock
This parameter specifies the source of timing signals for the dial backup port's transmit
clock. The available options are:
• External - the transmit clock derives timing from an external clock source.
When the DAP is operating over the DDS network and the External option is
selected for timing, the external transmit clock must be synchronized with the
network clock. Only phase differences are allowed when this option is selected.
The clock signals must be frequency locked.
• Slave - receive (Rx) channel timing is slaved to the dial-up Rx line and transmit
(Tx) channel timing is slaved to the Rx channel timing. Data is transmitted
synchronized to a clock derived from the receive line.
Call Progress
This parameter specifies whether the DAP observes call progress messages when
establishing a dial backup connection. By observing these signals (busy, ringing, etc.)
while a call is in progress, the DAP can reduce the time needed to verify a failed
connection.