gandrews@netcom.COM (Greg Andrews) (03/17/91)
In article <9908@discus.technion.ac.il> devil@techunix.BITNET (Gil Tene) writes: > >I have a setup that works pretty well for overseas calls. It uses >two undocumented T2500 registers : S120 and J6 S36. > >What works well for me is : AT S120=12 J6 S36=2 S121=1 > >To detail : S120=12 means no use only LONG packets, no micro > or medium sized packets. This cuts down heavily > on retrains. It makes interactive links much worse > but does'nt really hurt throughput. > No, S120=12 means use Long and Short packets, but no Micros. The setting for Long packets only is S120=2. > > [description of J6S36 deleted] > > [Gil's uunet throughputs deleted] > >BTW, does anyone know if J6 S36 is negotiable in the V7.0 PROMs ? >I really wish it was... > J6S36 is negotiable when you use a value of 4 (approx 90-100 ms tone). When J6S36 is less than 4, the modems do not negotiate the tone, and can have independent settings. This is true for all versions of firmware that support J6S36. Version 7 firmware has a feature where it can drop from a "plain" PEP mode (S120=0, J6S36=0) into a mode where the tone is sent before a packet (S120=0 J6S36=1) without needing to retrain. The modems do this "on the fly" based on the frequency and type of errors they are getting. This is part of the mods to PEP for better performance over fiberoptic long distance carriers, but it can come in handy over other lines also. Uunet currently uses version 7 firmware in all their T2500s. Given the throughput figures you quoted, an upgrade to v7 might give your connections a boost. -- .-------------------------------------------. | Greg Andrews | gandrews@netcom.COM | `-------------------------------------------'