Northern UTA220/UTA220k - Manual (Page 70)

9-2
UTA220/UTA220k
Rate Adaption
When using a rate adaption protocol, both the calling and
called units must use the same protocol. Also, unless the TA
is configured for T-Link “adaptive mode,” the DTEs on both
ends must be set to the same DTE speed before data can be
transferred. In the adaptive mode, the TA can adjust its speed
automatically to match the remote unit. To use this mode,
however, the DTE must also be able to change its speed
according to the connect speed of the TA, as indicated by the
rate in the connect message.
Flow Control and Pin Options
When using T-Link the flow control option for the DTE port
is overridden. In addition the RTS, CTS, and DTR pin options
are overridden. The T-Link protocol itself defines the way
these pins are handled.
T-Link transmits the state of the RTS pin to the remote TA
where it is transmitted back as the CTS state. DTR is mapped
to the remote end as DSR, but it is not looped back.
T-Link Options
Fixed/Adaptive:
• In fixed mode, the TA will not negotiate setup. If the other
TA is not set to the same speed the negotiation will fail.
• In adaptive mode, the called TA will be asked to adapt to the
originator’s parameters. If the called TA is set for fixed mode
and its parameters don't match the originator’s, the called TA
will request that the originator adapt to it.
RTS Assert/Normal:
• In RTS assert mode, T-Link operates as if RTS is always
asserted
• In RTS normal mode, T-Link passes the state of the RTS pin
to the remote TA
DTR Assert/Normal:
• In DTR assert mode, T-Link operates as if DTR is always
asserted
• In DTR normal mode, T-Link passes the state of the DTR pin
to the remote TA