bryan@marlin.NOSC.MIL (Dale Bryan) (04/25/91)
i'm looking for info on board level modems that are currently on the market that have the following features: full duplex and half duplex operation v.22,v.26,v.27,v.29,v.33 compatibility fallback from v.33 to all the above standards adaptive echo cancellation and equalization adaptive carrier deviation correction small package size also, does anyone know of another multicarrier type modem besides Telebit modems. thanks in advance dale bryan email: bryan@marlin.nosc.mil
tnixon@hayes.uucp (04/25/91)
In article <1744@marlin.NOSC.MIL>, bryan@marlin.NOSC.MIL (Dale Bryan) writes: > i'm looking for info on board level modems that are currently > on the market that have the following features: > > full duplex and half duplex operation > v.22,v.26,v.27,v.29,v.33 compatibility > fallback from v.33 to all the above standards > adaptive echo cancellation and equalization > adaptive carrier deviation correction > small package size This is a strange request -- because, of the five modulations you've listed, four are _leased line only_; only V.22 is for dial-up. V.26 _bis_ and V.26 _ter_ are dial-up modems, but not V.26. V.27ter is dialup, but not V.27 or V.27bis. V.29 is not dial-up, although some companies have produced proprietary half-duplex versions of V.29 for dial-up applications. V.33 is definitely not suitable for dial-up, because the turnaround time in a half-duplex mode would be on the ourder of 1.4 seconds. I know of NO modem that implements all of the modulations you're looking for -- in fact, I don't know of any that even support two of them. You rarely see modems intended for leased-line use combined into a single box (and definitely not with automatic fallback!) Can you explain your requirements a bit more? Why do you need these specific modulation schemes -- all in one modem? > also, does anyone know of another multicarrier type modem besides > Telebit modems. The only other company I'm aware of that sells multicarrier modems for dial-up applications is Forval America in Midvale, Utah. Uh, on second thought, I think they've announced it, but that they're not shipping yet. Their design is for a multicarrier modem with echo cancellation (full duplex!), but I think they've been delaying introduction to see how the CCITT V.fast work progresses. I believe Ven-Tel also sells multicarrier modems, bbut they're licensed from (and probably built by) Telebit; Anderson-Jacobsen and DCA also (used to) sell repackaged Telebit Trailblazers. -- Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net