Research & Development
12. The Specification with Si3044
12.1 UModem Specification:
However, Si3044 cannot detect the parallel phone directly. It can only measure the
line voltage when the line is on-hook. And measure the loop current when the line is
off-hook. It will judge the parallel phone is off-hook according to some of pre-set
threshold. Refer to section 0 for details.
The main specification is that when bit2 of S63 is enabling, the modem is
allowed to use line when the parallel phone is not in use. (Flow chart is as the
following figure).
Old
function
Modem standby
Modem start dial
Check parallel
phone
Ask to connect
Current state
Modem On-hook
Send error
message
Parallel phone
off-hook
Parallel phone
on-hook
Parallel phone
off-hook
Use parallel
phone
Parallel phone
off-hook
Use modem
Parallel phone
on-hook
Modem on-hook
S63.2
Enable bit=1
Disable bit=0
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Revision 1.0
2003/6 From 3JTech