P300H P300 Series Modem Installation and Operating Handbook Page 190
Aux Port
Pin Number
Sync
Async RS422 usage
RS 232 usage
26
Tx Aux Clock out A
Tx Aux Clock out
27
Tx Aux Clock out B
n/c
9
Tx Aux Data in A
Tx Aux Data in
10
Tx Aux Data in B
n/c
28
Rx Aux Clock out A
Rx Aux Clock out
29
Rx Aux Clock out B
n/c
11
Rx Aux Data out A
Rx Aux Data out
12
Rx Aux Data out B
n/c
42
( )
Tx Aux Octet out A
Tx Aux Octet out
43
( )
Tx Aux Octet out B
n/c
44
( )
Rx Aux Octet out A
Rx Aux Octet out
45
( )
Rx Aux Octet out B
n/c
50
Ground
Ground
( ) indicates lines are optional
In
Closed Net Plus ESC
mode the aux port is not used.
In
IBS
modes the Aux port can be set to both `INTELSAT` (using TS32 bit 1) and `Sync` modes
(selectable to use any of TS16, TS32 bits 1& 5-8, & TS48). In both modes a clock is provided and the
port can be used synchronously (with the clock), or asynchronously (allowing the async data to be
oversampled by the higher rate clock). In this oversampled mode (as specified by INTELSAT), the
Baud rate is limited to approximately 25-33% of the synchronous clock rate.
In
IDR
modes the Aux port provides either 32 or 64kbps data access in place of either one or both of
the 32kbps ADPCM audio channels. Typically this would be used synchronously, but if required it
could be used asynchronously & oversampled giving maximum baud rates of approx 9600 Baud (in
place of one audio channel) or 19200 Baud (in place of both Audio channels).