22 Configuring PAD/ATPAD Ports
PAD Port Configuration
PAD Port Configuration for Autospeed
Introduction
Autospeed is a convenient way to configure a PAD port's speed, especially when you
want a mix of terminal speeds. For example, autospeed is useful when the PAD port
is connected to a modem that is being called by devices with different speeds.
Implementing
Autospeed
To implement autospeed, set the Port Record parameter Port Speed = AUTO.
When the device calls the port, the port determines the speed of the device and
programs its I/O drivers to match the device's speed.
Auto Baud
Sequence
Parameter
A related parameter that affects Autospeed is the Auto Baud Sequence (in the PAD
Port Record). This parameter specifies the Autospeed Recognition Character that the
port uses to set the correct speed. These are the settings available under the Auto
Baud Sequence parameter:
• CR_Only: Autospeed on <CR>.
• CR_DOT_CR: Autospeed on <CR>.<CR>.
• TYMNET: Autospeed on the letter “a” (must be lower case).
• TELENET: Autospeed on <CR><CR> for 1200 bps or lower and @ <CR>
for 2400 bps or higher.
The default is <CR>. The autobaud feature is extended to support 14.4 Kbps, 19.2
Kbps, 28.8 Kbps, and 38.4 Kbps for all autospeed recognition characters. These
speeds are not supported on the UIO or AIO cards.
Autospeed Inter-
Character Delay
Inter-Character Delay is the transmission time interval between characters. For
example, Figure 4 shows the autospeed inter-character delay applied to the
CR_DOT_CR sequence presented above.
Figure 4. Autospeed Inter-Character Delay
Reduced
Autospeed Inter-
Character Delay
When using a dialup modem with a POS terminal or PC to send an Autobaud
Sequence, problems may occur if the inter-character delay applied to that sequence is
less than 180 msec. To overcome this, you must enter a CSK
(5ERWXW2F76XHLTTUUZC3) to reduce the inter-character processing time to
100 msec.
Note
Reducing the autospeed inter-character delay also has the effect of increasing the
minimum supported autospeed to 300 bits/sec.
CR
CR
.
(dot)
100
msec
100
msec
Autospeed Inter-Character
Delay
Autospeed Inter-Character
Delay
