Specifications

Excalibur Multirate DAP Installation and Operation
5-16
• V.13 - is only supported when the port is configured for synchronous operation.
If RTS Simulation is enabled at the far-end port and DCD Simulation is enabled
at the local port, when the far-end port raises RTS, the port transmits a 24-bit Up
code to the local port. There is an RTS-CTS delay to allow the far-end port
enough time to transmit the Up code before accepting data from the DTE. The
RTS-CTS delay is dependent on the port speed as listed in Table 5-3. When the
local port detects the Up code, the port raises DCD and is ready to receive the
data transmitted from the far-end DTE. After the far-end DTE has transmitted its
data and drops RTS to the port, the far-end port transmits a 128-bit Down code to
the local port. After the local port detects the first 48 bits of the 128-bit Down
code, it drops DCD. This means the DTE will receive the first 48 bits of the
Drop code. RTS-DCD Simulation may be configured to work in either or both
directions (inbound to or outbound from the central site).
• Out of Band - can be used when the port is configured for synchronous or
asynchronous operation. Signaling is carried on the portion of the aggregate
bandwidth allocated for unit to unit non-interruptive secondary communications.
This method does not add bits to the user data stream and allows the use of RTS-
DCD Simulation with equipment that is sensitive to in-band signaling. Table 5-4
lists the RTS-DCD worst case delay related to out of band RTS-DCD Simulation.
Notes: When the DAP's aggregate rate is 19.2 Kbps or lower, out of band signaling
requires that you leave 1.2 Kbps of the available bandwidth unassigned to the port.
Out of band RTS-DCD Simulation is not provided during dial backup operation for units
equipped with the Analog or ISDN IDBU feature.