eyh@quiet.Eng.Sun.COM (Chuck Hsiao) (05/30/91)
I am looking for a DSP board with analog telephone interface such that a data modem can be implemented by software only. Any information or pointers will be greately appreciated.
phil@east.Berkeley.EDU (Phil Lapsley) (05/30/91)
If you don't mind building some simple hardware, you can build the telephone line interface yourself and connect it to a DSP and AD/DA board of your choosing. Cermetek Corp. makes some fairly cheap (between $30 and $100) phone line interface modules (e.g., their "CH1811 Registered Telephone Line Interface"). They take in a telephone line (tip and ring) and split it into receive and transmit audio channels (1 vpp in and out), and also give you TTL level controls and indicators for off hook, ring, etc. The only thing you really need is power, a case, a handful of resistors, some wire wrap, and maybe an op-amp to convert the audio levels to the range of your AD/DA board. We're in the process of building one for our DSP lab here, to be connected to an Ariel ProPort AD/DA board and a BCE/Ariel S56X SBus DSP56001 board. If you want to avoid building the (analog) hardware, you might check out Atlanta Signal Processors, Inc.'s (ASPI) "Serial Voice Interface" box with the telephone line interface option. This is a small box that has a TI TLC32040 14 bit codec, telephone line, and telephone handset interface. The data from the codec is output via RS 422, and it's then your problem to get it into the DSP of your choice. The price? $895.00 (as of December 1, 1990). Seems kinda steep, but some people really hate to wire wrap. :-) Also, note that I have no experience with this board, and I'm basing the above on product literature. You might also ask Ariel Corp. if they're working on something similar; I've heard rumors that they are. Addresses: ASPI 770 Spring St. Atlanta, GA 30308 (404) 892-7265 Ariel Corp. 433 River Rd. Highland Park, NJ 08904 (908) 249-2900 Cermetek Microelectronics 1308 Borregas Ave. P.O. Box 3565 Sunnyvale, CA 94088-3565 (408) 752-5000 Phil Lapsley phil@ucbarpa.Berkeley.EDU ...!ucbvax!phil
smehta@kwela.nynexst.Com (Sandeep Mehta) (05/30/91)
> phil@east.Berkeley.EDU (Phil Lapsley) writes:
If you want to avoid building the (analog) hardware, you might check out
Atlanta Signal Processors, Inc.'s (ASPI) "Serial Voice Interface" box
with the telephone line interface option. This is a small box that
has a TI TLC32040 14 bit codec, telephone line, and telephone handset
interface. The data from the codec is output via RS 422, and it's then
your problem to get it into the DSP of your choice. The price? $895.00
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Phil has pointed at one set of solutions to work around building one's
own box, but we've had a snag w/ ASPI boxes...
We use the ASPI Serial Voice Interface and the Serial Audio Interface
box The latter is higher bandwidth (20Hz-20KHz) and more $$. But, and
here is the crunch, we can't seem to get the driver working for the SVI.
The SAI driver runs fine. Both drivers are developed in-house. We're
using it with a DSP32C based VME board (from Valley Instruments). ASPI
basically said that the problem is clock related, sorry, buy our SAI box
instead, and have a nice day! I'm debugging the SVI driver in the hope
that we can salvage the SVI based box(es).
Burr Brown also makes boxes, though they're very high (MHz) b/w for my
use. I didn't see anything in the VME/Sun world from Ariel @ ICASSP
this year...
so, caveat emptor...
sandeep
--
smehta@nynexst.com
--
"But jazz is decadent bourgeois music," I was told, for that is what the
Soviet press had hammered into Russian heads.
"It's my music," I said, "and I wouldn't give up jazz for a world revolution"
- Langston Hughesbrian@umbc4.umbc.edu (Brian Cuthie) (05/31/91)
In article <14157@exodus.Eng.Sun.COM> eyh@quiet.Eng.Sun.COM (Chuck Hsiao) writes: >I am looking for a DSP board with analog telephone interface >such that a data modem can be implemented by software only. >Any information or pointers will be greately appreciated. Buy a modem and reprogram the DSP. -brian