Dave
Some providers save $$$ by routing the international voice traffic component across an IP link. This is obviously a lot cheaper but there is a higher incidence of delays and/or duplex irritations. Check whether your telephony provider is using IP to route the calls and ? pressure them to increase the bandwidth.
Regards
JR
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1