gfs@druxu.UUCP (SkinnerGF) (08/24/84)
Thanks to all who replied to my inquiry about 1200 baud single chip modems. Here is a summary of all I heard and read. If you know of any not on this list, please tell me. Many speeds are included here for completeness. manufacturer / speed / notes chip number(s) specification EXAR XR-2120 300 / 1200 / 2400 $40 for the set XR-2123 Bell 212A or 201 XR-14412 CCITT V.22 or V.26 Micro Power Systems MP-7223 same as XR-2123 MP7224 1200 CCITT V.23 Texas Instruments 300 / 1200 TMS99542 Bell 212A, Racal Vadic 3400 TMS99531 CCITT V.22 TMS99532 TMS99533 TCM3101 1200 Bell 202, V.23 National MM74HC942 300 complete modem MM74HC943 Bell 103 $25 - 28 TP3310,11 122 / 600 TP3320,21 Bell 202s, V.23 AMI 300 complete modem S3530 Bell 103, V.21 S35212 1200 S35213 Bell 212A Rockwell Intl. R5312 1200 R5313 Bell 212, V.22 Motorola MC145445 300 Bell 103,113 for use on noisy lines MC6172 2400 / 1200 MC6173 Bell 201B/C, V.26 MC6862 2400 / 1200 Bell 201B/C, V.26 OKI Semi. 1200 $16 in large quan. MSM3953AS CCITT V.21, V.23 Silicon Systems 1200 SSI 223 CCITT V.23 Signetics up to 2Mbits/sec 2 wire FSK NE8050,1 FSK (similar to Ethernet) REFERENCES: Integrated Ckts Mag Jul/Aug 84 p11 A comparison of various chip sets Electronic Design Dec 22, 83 p111 A look at standards Electronic Products Jan 14, 84 p59 A guide to modem ICs Electronic Design Aug 4, 83 p123 NE8050,1 Electronic Design Jun 14, 84 p261 TMS99532, etc... Electronic Design Jan 12, 84 p325 MC6172,3 EDN Jun 9, 83 p75 Cermetek CH1760 212A modem hybrid module and some small single board 212 modems Electronics Jan ?, 83 TCM 3101 VERY good data is available from EXAR and from Micro Power Systems. Note that the modem chips can easily be connected to a phone line by using one of the new single chip telephone circuits. These will allow DTMF signaling etc.. A pretty smart modem could be made.