
A N 9 3
274
Rev. 1.4
A V.29 FastPOS Sample Program
Introduction
In previous versions of the interface to V.29 FastPOS, the HDLC layer was assumed to be implemented by the host
software. Another issue was the case where the EPOS Terminal was calling a server that could answer either as
V.29 FastPOS or V.22bis; it was not possible for the modem to “train down” to V.22bis.
To address these issues, a new interface has been implemented in the Rev D Si2493/57/34/15 and Rev A Si2494/
39 and is available as a patch in the RevC ISOmodem. This interface allows the call to start as a V.29 FastPOS
and can train down to V.22bis if the server NAC can answer as either a V.29 FastPOS or V.22bis. Please contact
Silicon Laboratories, Inc. for the latest patch.
One of the improved aspects of this interface technique is to use two control lines: (RTS and DTR); RTS controls
direction of transfer, while the DTR hangs up the line. The trade-off here is that RTS can no longer be used as a
method of stopping the modem from sending data to the host.
This is generally not an issue as long as the DTE rate is greater than the DCE rate and the host can keep up with
the receiver without having to resort to the negation of RTS.
The data are in V.80 format. Just read and write data while toggling RTS as needed. Assert RTS to transmit and
de-assert to receive. This is called a push-to-talk paradigm.
The description here shows how to set up and use the modem for V.29 FastPOS and also provides a sample
program along with both a DTE trace and WAV files that capture what is happening at both ends of the modem.
The only critical signals that are not recorded below but obviously controlled in the program are the RTS and DTR
lines.
The hardware used was the Engineering Eval. Board Rev 3.2 and a 24xx2G-DC Rev 1.2 module containing a 24
pin 2457 Rev C ISOmodem chip plus a 3018 DAA chip. JP6 was strapped {1-2, 4-5, 7-8, 10-11, 13-14}. JP5 was
unstrapped. The duration of SNRM and UA should be at least 453 ms. The host should add 450 ms more delay to
increase the UA duration, in case some old V29FC servers need 453 ms. Also, 100 ms should be added after
sending an RR frame.
Setup procedure:
1. Host DTE Rate must be greater than 19200.
2. Host DTE must be configured for 8N1 CTS-only flow control
3. AT+GCI=xxx
AT:U4D&BFF7
Disable and turn off the calling tone as +GCI may enable the calling tone
AT:U70|8000
HES = 1
AT&D2
Enables escape pin
AT+IFC=0,2
Flow control setup
AT+ITF=0383,0128
Set the parameters for hardware flow control
AT:U87,050A
V.80 Setup
AT\N0
Wire Mode
AT+ES=6,,8
Synchronous access mode
AT+ESA=0,0,0,,1
Synchronous access mode control
AT:U1D4|4000
Standard ePOS Flag
AT+FCLASS=1
AT:U7A|0009
U7A[0]=1(Fast Connect), U7A[3]=1(V29FC), U7A[13]=0 (EM-shielded half duplex)
AT:U7A|2009
U7A[0]=1(Fast Connect), U7A[3]=1(V29FC), U7A[13]=1 (RTS half duplex)
AT:UAA,4
Enables V29FC rude disconnect with &D2
AT:UD3,B4
V29FC answer-tone duration threshold = 180 ms
4. Make Sure RTS is negated (voltage high)
5. Make Sure DTR is asserted (voltage low)
6. Send ATDT###
Содержание Si2404
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Страница 27: ...AN93 Rev 1 4 27 Figure 7 Parallel Interface Read Timing Figure 8 Parallel Interface Write Timing ...
Страница 200: ...AN93 200 Rev 1 4 Figure 31 TAM Handset and Speakerphone Voice Paths ...
Страница 201: ...AN93 Rev 1 4 201 Figure 32 Si3000 Codec Gain and Signal Selection Options ...
Страница 290: ...AN93 290 Rev 1 4 Figure 57 256 Band Spectral Display Figure 58 2048 Band Spectral Display ...
Страница 305: ...AN93 Rev 1 4 305 Figure 76 Parallel or SPI Port Interrupt Service Flowchart ...